Sorry if this is too technical.

lol this is my wheelhouse.

chmod, as well as a lot of other commands, support recursively operating on a path themselves; chmod -R.

More generally, I'd recommend using find -exec (man find), which you can pass flags to filter what you want (e.g. -type f for only files).

While most commands expect a list of files to operate on as their arguments and not in stdin, xargs transforms lines from stdin to command line arguments.

In simple cases, you can use a shell for loop as follows:

for file in directory/* ; do
  echo "$file"
  do_something "$file"
done

I wouldn't recommend ever using ls in scripts; it's made to output human-readable text and not something that a script can reliably parse (think of edge cases like a filename with embedded newlines).