Testable and self-contained bash script
Good

good indentation
somewhat helpful comments
good to do the ; then bit on the same line as the if

Suggestions

use double brackets for conditionals
try shellcheck (It will tell you to put quotes around your variable substitutions.)
put your arguments into named variables so you don't keep have to referring to $1
put the 3 sections into if...elif...else structure to make clear that you're only going to go into one of them
check for the existance of ./done.sh at the beginning
explain what the goal of the script is somewhere.