The fastest way to learn this is to build it
UpX is software. Somebody has to build it. The best people on a course are usually better off working on something real than doing another exercise.

How it works
The idea, plainly
A small number of people who finish well, working on the actual product with the people who built it. Not a volunteer scheme, and not free labour.
Work on the real thing
Real users, real bugs, real code review. An exercise has no consequences, and consequences are what teach you.
Reviewed by the people who built it
Your work is read by whoever wrote the part you are changing. That is the loop that actually makes somebody good.
Paid, if it is real work
If somebody is shipping something we depend on, they are working. We would rather say that now than discover we disagree about it later.
Why it works
What you walk away with
Build well and we come to you
Strong marked work is your invitation, so there is nothing to write and nobody to chase. The crew stays small, which means your changes get read properly.
Paid to ship real software
You are paid on what you deliver and reviewed like any engineer here. You leave with production work on your record, on software people depend on.
The rest of UpX is on the UpX overview.
Where to start
Start where you stand
Take the short assessment, get an honest read on where you are, and begin on the track that fits.