A small guide to start creating your team

Dictionary

Tank- A tank is a pokemon with high defense/special defense, usually has low speed and high attack/special attack.
Sweeper- A pokemon with high speed and attack/special attack, usually has low defense and special defense.
EVs- stands for effort values, each pokemon can have up to 510 EVs, each stat can have up to 252 EVs. I will not expend about how EVs are gained as it is irrelevant to the topic but if you are interested you may try and google it for detailed guides.
IVs- stands for individual values, a pokemon is born with random IVs on each stats, IVs move in the range of 0-31, the higher the IVs on a certain stats are, the more this stat is boosted.
Setup- In PvP, many people use setups, which is using a move such as sword dance (Which doubles attack) before attacking or using moves such as stealth rock (Which damages a pokemon the enters the battle).
Natures- each pokemon has a random nature, natures may be natural (don't change any stats) but most of the nature reduce one stat and raise the other as displayed in the table.

All of those words are important and effect directly on how good a pokemon will be on PvP.
Types
Each pokemon has up to two types, a good PvP team must have a good type cover, for example, if you use a full fire type team, a single water type might be able to beat you easily, it is highly recommended to have pokemon with different types on your team.
Each move has a type, a fire type pokemon may still learn a grass type move, which gets us to our next topic:
moveset
A moveset is simply the moves a pokemon has.
As you might know (and if not I'm here to tell you now), a pokemon can only learn up to 4 different moves, which is why having a good moveset is important, first of all, a good moveset must be able to cover as many types as possible, a lot of movesets may also countain setups.
EVs, IVs, and natures
In the dictionary you learned about what are IVs, EVs and natures, but how do you use it in order to help you in battles?
It's actually quite simple when you learn the basics.
Each pokemon has its own uniqe base stats, most of the pokemon have higher stat on one kind of attack over the other, a pokemon with a higher physical attack is called an attacker and a pokemon with a higher special attack is called a special attacker, a good nature for a pokemon depends on what stat you want to raise, however, it is usually a nature that reduces the kind of attack that the pokemon is lacking. A special attack needs to use special attack while an attacker should use physical attack, which is why the other kind of attack has no use for them and reducing it will not affect the pokemon.
IVs are described by the amount of max IVs a pokemon has, for example, a pokemon with 31 IVs on all his stats will be described as 6x31.
However, there is no actual need for a pokemon to have 6x31 IVs, as mentioned before, there's a useless stat on each pokemon, so 5x31 is not different from 6x31.
A pokemon shouldn't have any EVs on his "useless stat" either, as it is a waste of slots.
The stats you should EV train a pokemon in are different for each pokemon and for what you are using it, a sweeper for example, should have max EVs on speed and attack/special attack (Depends on whether it's an attacker or a special attacker), a tank on the other hand, should be EV trained on defense or special defense.

The battle
Alright, so you made a good team, trained it well and gave it a good moveset, what's next?
While in the battle you must know what to do, if you are in a type disadvantage, maybe it might be a good idea to switch pokemon.
You also must know what moves will be more effective on what pokemon, as well as what moves would be less effective, well, lucky for you, there's a chart for this one:
תוצאת תמונה עבור ‪pokemon type chart‬‏