I was confused before, but later I found a way. If you are satisfied, please adopt it! Forgot that talent has been adopted. The content is as follows:

First enter the "Start Menu", which is the page shown below.

Sogou asked.

then

Delete: Click the icon to delete, and be careful not to put it down. Just drag it into the red box on the left.

Add: On the other hand, click the application icon in the red box and drag it to the right.