Won't start, clicking noise even after I turn the key back. 07 f450.

Did you try starting in neutral? Could be the neutral safety switch. Try shifting thru the gears with your foot on the brake and turning the key. If it tries to start in another gear, adjust or replace the neutral safety switch. If not that, is there a security light flashing? Could be a problem with the security system.

Try cleaning battery terminals

check coils, plugs, clogged throttle body, vaccume leaks, or anything else that would enable from starting.

that item is called a relay switch. it toggles on and off depending on which electrical component it is connecting. if it's blown, they are cheap and easy to replace like a fuse, but you'll need to look at the fuse box chart (usually on the underside of the lid) to determine which one and where it's located. You can't look inside the relay to determine if blown, but you can replace them one at a time to test...
Also, if you're experienced in electrical, a paper clip can be used when the relay is out, to connect the circuit that you need. use tools and or gloves when attempting this method.

sound you have a blown clutch slave cylinder

You have a defective battery.

more then likely its a bad starter. or the cable to starter.

It's your starter. Find location of your starter. By the flywheel. Then. Bang on it . Your car will start. You still need to replace the starter.

Get hold of a scanner and find the code that comes out of your truck. Then start there.

I would check your battery. I would also look for loose grounds. The clicking you hear is your fuel pump turning on. I would check your battery voltage and, have the battery load tested.