Yes you need either to repair the pulley (ie weld the lug back on) or replace it - expect to pay around £40+ for a pulley.

There are plenty of threads on here about crank/cam/dizzy timing - try the search function (if it works).

Basically, the crank pulley has a V notch in it - DO NOT use this mark, but line up the trailing edge of the lug closest to the notch (crank rotates clockwise, so the left hand edge) with the marker on the front cover, the cam pulley pointers should point to each other, and the centre of the rotor arm with the small notch in the dizzy body directly beneath the rotor arm.

see here

https://passionford.com/forum/viewto...ghlight=timing