NEED ADVICE - Building my first over Pokemon team (OU)

[WilliamH]

Hey everyone, 
I recently started playing PokeMMO and I wanted to start playing PvP. 
I started with playing randoms and I really like the PvP scene. 
Now I am trying to build my own OU team, however I am having difficulties coming up with a (full) team. 

My favorite pokemon is Scizor, so I put that one in my team. 
I watched a lot of videos on how to build a PvP team, but I am still struggling. 

 

This is the team I came up with so far;

https://pokepast.es/64fef70a81c55736
 

My thought process: 

I thought Scizor and Garchomp were both strong attakers and I saw them matched together a lot. 
I picked Rotom Wash cause it looked like a great tank that is still strong. 

 

However, I do not know which other three pokemons I should pick to complete my team?
Do they need to be walls? Or do I lack a special attacker?

 

I am open to any advice! 

Thanks in advance. 

Edited January 8, 2023 by WilliamH
Added a picture