I'm new just made this account, I've seen a series on a channel call summoning sault and that made me want to look into speed runs, I've never done speed runs before any suggestions on a place to start?

I have a Ps4 ps3 ps2 3ds a switch and I use steam quite a bit.

Welcome.

It depends on what approach to speedrunning you're interested in. First take a look at the games you have and ask which ones you're willing to play through 50 -100 times through to completion. Play one through, take notes on what steps you need to accomplish to beat the game, and find out if you can optimize the path between each step. Try to skip steps along the way to see what happens. That's the routing of a speedrun. If you don't really enjoy that part you can find games with existing runs, and use the same route to improve the time. Either way, that's the next phase, getting practice doing the route. Little by little (or a lot in the beginning), you'll get faster times. Congratulations, you're doing speedruns.

After that you might look into how to record your runs and submit videos here.

Good luck, have fun.