Dead easy to do, as said get a proper kit, this will have the correct length TDC pin in the kit.
Take the plugs out when doing it, that way when rotating the engine by hand you have actually hear the ping/knock as the crank web contacts the pin, the flat bar is used to lock the cams, make sure you do undo the cam bolts, just 1/2 turn is plenty so when belt is tensioned they are free to rotate slightly.
Prior to fitting the tdc pin line up on tdc by the cam slots(these are offset so bar only goes in one way), then rotate counter clockwise the crank about 30 degrees, insert pin after removing the 10mm bolt at base of block, make sure it is screwed in fully, then when you rotate the crank CLOCKWISE you will hear and feel it contact the pin.
Just be aware there are 2 different types of rocker cover gaskets, buy both and take back the incorrect one for refund, the last one i bought from ford for a 2L ghia mk1 focy I used the reg number, and it was still wrong!!, luckily I decided to get the "wrong" one at the same time which was correct!!
tabetha