New to Unreal, first project - any tips?

Hey, started using Unreal for a project, long time Unity3D.
Originally tried Cryengine but it has the worst work flow imaginable. been playing with unreal and its so much better, always loved unreal and glad to see it being more user friendly and feature packed then older versions.

anyway, this project is a simple exploration/open world game for therapeutic purposes, but I’m having trouble trying to compile a build with an open world map

its supposed to be a giant island in the ocean (with swimmable ocean)

one issue that is bugging me is scale, the fact it uses % instead of meters, makes it confusing when you want to specify distance on a terrain.
since I have an ocean, and having a giant plane might be problematic, I used a terrain layer for the ocean, so i could hopefully blot out the ocean in parts i dont want it (like underground caves)

ideas? tips? things to be aware of?

Unreal’s unit scale is meters, the scale you’re looking at is the relative scale of the object - the object already has a given size (in meters), and that variable you’re describing is the percentage size you want it to be.

A landscape is a subdivided plane with that by default has one vertex per meter, and a scale 100 landscape is up to 256 meters tall. From there you can work out exactly how big your landscape is.