I think @textilestechs still do weekly or maybe fortnightly meetings that helps get beginners started, maybe attending one of those would be a good starting point. See what they advise.
the drawer in the bottom of the shelves in the textiles area is full of scraps which you can use, though for jumpsuits the tricky part will be if it’s using stretchy material, there should be some jersey to practice with somewhere, or you can buy a scrap cheap at simply fabrics in brixton or use some old cheap t-shirts, and you can sew it betwen some paper to stop the issues with puckering.
Other than that honestly give it a go with the machines we have, if you need one to one guidance (you should be able to pick it back up like a bike if you give it a go, though for threading you can see online diagrams if you google the machine make) then people tend to be in on sundays
Looks lovely! Where is the pattern from? Would be helpful to see what they say in the blurb about it.
If you don’t want to go straight in with your final fabric you could start with a mockup in something that’s a similar weight and/or practice any seams/fiddly bits like the buttonhole on some scraps so you’re confident when you start with your good fabric.
I reckon it’s totally achievable by Christmas! Hoping to be in the space a bit in the next few weeks so can help in person if needed.