If you're just now coming over to Linux, you might have noticed there are a lot of distributions to choose from. One of your first choices will be what base you want to use. Here's a bit of help.
You also don't need to switch to any GUI tool for checking or analyzing disk usage. Tools like ncdu, top, and htop show you ...
There are instances when a GUI file manager just won't work. When I run into those situations, there are several terminal-based options I go for.