Godot does have a visual scripting system, node based like unreal BP, but can be a bit rough to learn in the short time of a jam (some people have learned visual scripting quickly, but not that fast) so GDScript may be easier.
If you used Construct also you may be facing several challenges like a different way of structuring games, written code, and according to your question, a third dimension too. It is always advised to try to tackle one thing at a time so try first, like the jam theme says, something simple.
Later the migration from 2D to 3D in Godot is simple in terms of logic and basic structures, is just complex in the same way 3D is complicated in general.
Back to programming.
Sadly, and despite that GDScript is a nice and simple starting language for learning programming, there are not many resources to start learning from zero (yet), people is usually directed to sites like https://www.learnpython.org/ which cover the programming basics with a language similar to gdscript, then the official documentation and try to experiment.
That said, here are some video tutorials focused on programming made by godot contributors and content creators:
Create a game with visual script:
Intro to GDScript:
A long tutorial about GDScript: https://www.youtube.com/playlist?list=PLJ690cxlZTgL6KVSNl5RVKZ0O1_oD5BWB