Replace fuel filter: release pressure?

The insert for my new delco fuel filter says only to have a professional install, and that the fuel system needs to be depressurized before doing do. How is this done?

remove gas cap for starters....

remove gas cap for starters....


Thats all you are going to say ??

there is a shroeder valve on the fuel rail put a rag over the end of it and push the valve core in to release the pressure

thanks
Now i will do a word search for Shroeder Valve.

it looks like a tire valve where you put air in and it is on the fuel rail. i think it is on the right front right under the upper plenum if you are looking at the engine