Use the "separated" file in your project's Extras folder.
Cricut Design Space doesn't easily let users "break apart" multi-part shapes. But sometimes you need to work with just one small part of a file. If you can't seem to delete shapes without deleting too much, you may need the "separated" file.
The "separated" file is in your project's Extras folder. It is named "entire_project_separated.svg." Your project's name will be part of the filename where the word "project" is.
So for the Baseball Cap project, its "separated" file is named "entire_baseball_cap_separated.svg."
The "separated" file contains all shapes for your project saved "separately." You can upload/insert it into Cricut Design Space and then delete the parts you don't need.