Have you reset the carb? If the seals leak and the carb was tuned to compensate, it will now be way too rich with new seals.
Either way - setting points:
Turn the flywheel until the piston is at TDC where the points are open theirnfullest, adjust their gap between 0.3mm - 0.4mm
Then adjust the armature plate so that the points first break when the mark on the flywheel aligns with the mark on the case.
If you have a feeler gauge, use the thinnest one and insert it into the points gap, turn the engine over ajd the feeler gauge should slip out when the timing marks align.
That’s a “close enough” to get it to run. Ideally you’ll use a multimeter to fine tune when the points break and a dial indicator to set the timing.
See how you go