Nail polish can be used with base coat for ordinary nail polish and finishing gloss top coat, also for ordinary nail polish.
Base coat - it is nail polish which dries out on air and it is placed under ordinary nail polish.
Finishing gloss top coat - it is top coat which you put on top of ordinary nail polish and it dries on air
Only after you apply base coat and top coat you can expect that the nail polish would last longer than 7 days. Besides that, if we apply base coat before nail polish in color, the nails look much prettier than without base coat. For longer lasting we apply top coat.
You can apply nail polis on pre-treated artificial nails and transparent gel polish. But only as the last layer and do not put it in UV or LED lamp.