Instr() Function take the Index if it find the given text in the defined string. So the simple solution of the problem is
if Instr(string from where to search , string that is searched) > 0 then
"Type the message if the search is successfull"
"Type the message if the search is Unsucessfull"
I hope that you will understand it this time and after then in entire your life you will not forget it.