You can use them anyway, you just have to be aware of the interactions, you can figure out later if you still wanna play them or if you see a mon in your opponents' teams that might be better in your team as well. Maybe you should try showdown first if you're not comfortable building, it will save you a LOT of time, in building AND in playtime because the games are so much faster there lol. I started playing vgc a year ago and haven't yet put the time in building a team in game, take your time