[RATE MY TEAM] Need help building my first competitive pokemon

[Gentleman]

How do you do!

I can recommend you mine two I won the Battlezone with
1.) Garchomp; jolly nature; ability: roughskin; item: rocky helmet
Dragon claw
Earthquake
Firefang
Swords dance

2.) Milotic; bold nature; ability: marvel scale; item: left overs
Recover
Confuse ray
Ice beam
Scald

I hope that was helpful. Have a good one!
Best,
Gernot