Standard timing for a 3T GTE is 12 degrees before TDC. There are 2 marks on the main crank pulley. Looking from the front of the engine the one most anti clockwise is TDC and simply timing so the next mark (more clockwise) is in line with the pin thats mounted to the front timing chain cover and your done. That mark is 12 BTDC.
To adjust the timing, loosen the bolt under the dizzy, run the engine and slowly rotate the dizzy until the mark lines up. Do this with the vacuum line to the dizzy removed so the timign doesn't advance at all.
Obviously you need a timing light to do this. If you don't have a light, then dont mess with it.