I begin by removing the glow plugs - releases compression and easy to turn the engine over with some precision.
Rotate engine and use locking pins to locate the flywheel, camshaft pulley and injection pump to check the alignment of said points.
Grab a Haynes manual it is very good at timing belts ... also the '55 can have crossover features with the 2 litre engine which affects how the belt is installed.
That's my advice for what it's , basic to start yes but the detail will take many words.
Agreed. Just don't force engine to turn if you feel a *hard contact*
If it has jumped, pin the cam and pump first with the crank about 45 deg before TDC/1 and bring crank up to TDC and then pin it- This will prevent piston/valve contact