^^^ What Bondo said, but let's give ya' a push too:
Tilt on a Stringer is an electric motor that drives a gear and clutch pack on the intermediate housing (part that passes through the big ole' rubber boot). You can find it easiest by locating the the apparatus that isn't working when you really want it to
The motor is on the inside of the transom, port side (right looking at the engine from the front of the boat). If you're hitting the switch, hearing the solenoid click and then nothing happens - it's likely that that motor is not working and needs rebuilt (or replaced).
Trim is a whole different ball of string. You may have a hydraulic system or a mechanical (like mine). Again, it's easy to locate in that it's a very similar motor to the other one that isn't working
The mechanical system is located on the front engine mount, the hydraulic is typically on the side (I think).
Tilt is strictly for getting your drive up for trailering. You don't want to run the engine with the drive up over about 700 RPM (essentially making steerage in shallow water if you have to). Underway, you want to have your drive tilted full down.
Trim is how you adjust the attitude of the engine against the boat thus affecting how your boat runs across the water. You can trim anyway you want at any speed - it's designed to handle it.
When you post about fixin' 'em, make sure you let us know what it is and isn't doing and if you've got a good manual to help ya' through it.
