Plastic welding use a 100 amp soldering iron with large tip basicly melt back together from behind,then I'd recommend some superglue to fill into it from the front can be sanded once dry careful use gloves or fingers dry quickly
I'd then use a fibreglass kit to reinforce inside depending how much area damage covered.
Get some old bits to practice on plenty of old broken car & mc bodywork laying about in bushes etc.
I've done quite a few jobs infact my 1st ever plastic weld job was on my 98 fazer 14 odd years ago
where does time go lol