Hi I am new and want to change which type of prime I'm looking for.
Currently it's 321-sieve.
Then you are not currently looking for any type of prime – you are running the sieve subproject which is basically a preparation task for future prime-finding done in 321 subproject. You cannot find a prime in 321-sieve subproject directly.
You can change what subproject you are running (what type of numbers you are prime-hunting or sieving) in PrimeGrid Preferences. It's a link in the menu of the website.