So I deleted everything I had installed and steo by step this is what I did:

I created the second script and called it usp.sh and I added it here:
/home/pi/RetroPie-Setup/scriptmodules/emulators

I then went into the setup script an installed usp from the experimental menu

I refreshed emulationstation by pressing F4

the +Start.sh file showed up in the zxspectrum menu.

upon selecting +Start.sh I pressed “m” and changed the default emulator to usp