What IPTV Smarters Pro actually is
IPTV Smarters Pro is a player. It holds no channels of its own, sells no subscription, and works only once a provider has given you credentials to put into it. That distinction matters on day one, because the app being free leads people to assume something is included with it, and nothing is.
It also is not a single app. Several near-identical players ship under similar names, and providers hand out whichever build they have tested, so the screen in front of you may not match a screenshot you found elsewhere. The layout differs; the three things it asks for do not. If your provider named a specific build, install that one rather than the closest match in a store search.
Work out which of the two credential types you were sent
This is the step that decides whether the rest goes smoothly. Xtream Codes credentials arrive as three separate values - a server URL that looks like http://example.com:8080, a username, and a password - and they are entered under the login option that asks for exactly those three fields. An M3U playlist arrives as one long web address, often with the username and password already inside it, and it belongs under the option that asks for a playlist URL instead.
People fail here by splitting an M3U link across the three Xtream boxes, or by pasting a server URL into a playlist field. Neither returns a useful error; both look like a rejected login. If you have one long link, you have a playlist. If you have three short values, you have Xtream Codes. Prefer Xtream Codes when a provider offers both, because it carries the programme guide and channel groups that a bare M3U link often will not.
Install it on the device you actually watch on
On Android TV, Google TV and Android phones or tablets, the app is in the Play Store and installs normally. On Fire TV, availability moves around by region: when it is in the Amazon Appstore, install it there, and when it is not, it has to be sideloaded, which means enabling installation from unknown sources in the device settings and fetching the file with a downloader utility. On iPhone, iPad and Apple TV it comes from the App Store, and on Windows and Mac there is a desktop build.
Roku is the exception, and it catches people out often enough to have its own guide on this site. Roku does not permit sideloading, so a player of this kind cannot simply be installed the way it can everywhere else. Check that page before buying hardware on the assumption that any device will do.
Load the playlist and let the first sync finish
After the credentials go in, the app fetches the entire channel list and, on a large lineup, this takes longer than people expect - a minute or two is normal, and on a slow first connection more. The screen can look stalled while it works. Backing out and retrying at this point is what produces the impression that the login failed when it had actually succeeded.
When it completes you should see channel groups rather than one undifferentiated list. If you see a flat list with no categories, or a fraction of the channels you were promised, the playlist loaded but the grouping did not, which usually means an M3U link was used where Xtream Codes were available. Re-adding the account with the three-field option generally fixes it in one step.
Add the programme guide so it is not empty
A freshly configured player shows channels with no schedule against them. The guide data is a separate feed, and with Xtream Codes it is usually pulled automatically once the account syncs; with an M3U playlist it often has to be added by hand, using a guide URL the provider supplies separately.
Give it time before concluding it is broken. Guide data downloads in the background and can take several minutes to populate, and a schedule that is present but shifted by a fixed number of hours is a time-zone setting rather than a missing feed. What an EPG is and why it goes wrong is covered in its own guide here.
The few settings worth changing on the first evening
Three are worth your attention and the rest are not. Hardware decoding should normally be left on, because it hands video work to the chip built for it, but on an older box that stutters or shows a black picture with working audio, switching it off is the fix. The default player choice matters for the same reason: if a channel plays sound without a picture, changing which internal player handles the stream usually resolves it.
The third is the stream format, where a provider offers both HLS and MPEG-TS. On a stable connection MPEG-TS tends to start faster; on a congested one HLS recovers more gracefully. There is no universally correct answer, which is why it is a setting rather than a default, and it is worth trying the other one before assuming a channel is broken.
If the login is refused
A rejected login is a different problem from a setup problem, and it has its own page on this site because the causes are specific and ordered. In short: the credentials are almost always the cause, the app almost never is, and reinstalling is the least productive thing you can do first.
Work through that guide rather than guessing here. The one thing worth checking before you leave this page is whether you split an M3U link across three Xtream fields, because that failure looks exactly like a wrong password and is fixed by re-adding the account the other way.
What a player cannot do for you
No player fixes a stream. If channels buffer at nine in the evening and behave at noon, that is congestion somewhere between the provider and your living room, and every app in this category will show it. Switching players to solve stuttering is the most common wasted afternoon in IPTV, and the buffering guide on this site works through the causes that actually respond to intervention.
What a good player does is get out of the way: load quickly, group channels sensibly, show an accurate schedule, and change channels without a pause. Those are worth having and they are worth choosing between, which is what the player comparison guide is for. Stream quality is bought from the provider, not installed.