first off, u will need a plastic aheasion agent. this might be difficult due to the fact that honda uses recycled plastic and mixes ridged and semi ridged plastic together, this is why all honda replacement parts come primered.
u will need to get a bodyshop that knows this and get the product to spray on there that will all for the scealer to adhear to the side skirt.
thats one reasion bodyshops are not really suppost to do major repairs on honda bumpers due to the fact bondo will not ahear to well to it.
to prep it u will need a paint safe degreaser, and scuff pad or wet sand 1000 grit. if u have any scratches u can take some wet sand 400 to it lightly just take ur time but u cannot go courser then that. dry off and paint.. its not that hard, it just depends on how good u want it to look.
if u have access to sikkens paint brand: u can buy the plastic aheasion in a spray can style as well as primer in a spray can, the plastic aheasion agent is called plastoflex
and the primer is a sikkens brand that comes in a white can and it works good, shake it up good also, id apply 2 coats of the plastic adheasion, then let it dry for like 15 mins the spray the primer on, give it like 4 coats,let it dry for a half of day then sand it down with some 600 grit. then clean it with some water, the ur ready to paint. also dark greens and blacks and blues covers anycolor well, only dark reds donot and some slivers, and whites
goodluck let me know if u need any help.