Broken timing belt, interference engine--mechanical novice here

[Doug Tatham]

In the Haynes manual it tells you that after you set the tension, rotate the engine twice (4 revolutions of crank shaft) and back to TDC (top dead center), then check your timing marks again. When you tighten the tensioner, you can go in either direction. If you go in the wrong direction you won't be able to put your timing belt cover back on. If you hear squealing after changing the belt, it means you tightened it to much. You should be able to twist the belt 90 degrees with your forefinger and thumb.