Sounds to me like one of the tilt switches is closed , which is why the game is in TILT. There are usually at least 2 or 3 tilt switches.
One will be on the bottom of the playfield somewhere, one will be on the playboard (the board in the bottom of the cabinet with the score motor etc)

Find these and check to make sure they are open , also check the slam tilt switch on the coin door (if there is one) ..

You will find EM's are not that hard once you get used to them .. usually problem will be a switch out of adjustment , or a wire has come loose .

I have found the best thing to do when you get an EM is give it a complete mechanical overhaul , but can appreciate you probably aren't ready to start pulling apart your only Pinnie just yet.

Good luck with it and have fun

Cheers
Dave