I enjoy the game and I enjoy speedrunning, how do I start learning how to speedrun this?

You have to click fast.

learn builds and do faster

Okay, is there any specific resource to learn the builds or do I just watch the runs? Also, in a game I saw some people talking about maybe a practice server, do you have any idea what that is?

Watching runs can really help to show the strats that ppl come up with for builds.

The simulators can be accessed from this video:

The discord isnt linked to src for whatever reason but you can join it here: https://discord.gg/6JnDUqx

I also plan to make a video going in further detail on how to play competitively for newer people, I just havent gotten around to doing it yet. Hopefully this helped :p

Thanks! Definitely looking forward to your video if you make it.