doesn't accept <things inside code>

This:

Exactly! You understood correctly. The syntax is %~<option><letter>, where:

• %<letter>: is the loop variable (e.g. %A, %B), which stores the values of the files or parameters passed to the script.

• ~<option>: is the modifier you use to extract specific parts of the path or file.

saves as:
Exactly! You understood correctly. The syntax is %~, where:

• %: is the loop variable (e.g. %A, %B), which stores the values of the files or parameters passed to the script.

• ~: is the modifier you use to extract specific parts of the path or file.