Hi @Fula!
The ODK-X docs: ODK-X documentation — ODK-X Docs
and especially the example apps: Trying Out ODK-X Tables — ODK-X Docs
are a great way to learn about ODK-X
I also did an intro training (slightly earlier version of ODK-X) with slides here: Community contributions to upcoming ODK 2.0 documentation refresh - #2 by elmps2018