>>22364734Apart from that, play a lot on showdown, it's faster to make teams so if you keep losing and need to modify something you'll do it in a minute instead of a day.
Once you're satisfied you can choose to keep playing on showdown or play on cart ranked.
If you don't know how to use a pokémon check Smogon, but just for reference, in the long run you'll notice you don't really want to use some sets but tweak them to fit better your playstyle (though some mons aren't that tweakable and their smogon set is the best one).
Other that, play a lot and don't give up because you're going to lose a lot until you start understanding how the metagame (who's the most used mon, what mon is the biggest threat to your team etc) works.