macOS Disk Space

The most simple and available option for assessing disk space and finding what is taking up all the space is Storage Management, which is well documented at How to free up storage space on your Mac - Apple Support. The "Large Files" option allows you to quickly find the biggest files, but then "File Browser" helps you find the biggest folders.

If you are more of a command line person then the following is useful:
du -h -d 1
This shows disk space usage, in human readable form but to a depth of 1 folder, making it simple to read. If you change "-h" to "-m" then the sizes are in megabytes and possibly easier to compare.

There are tools with easy to use user interfaces that also help with this problem, so here are some:

I have not personally tried any of these tools but know people that have recommended all of them.