if they are new, I would wipe them down with white vinegar to kill the residue on them from the newness. Then I would lightly sand the surfaces to rough it up a bit. This might not be necessary, as on old vinyl I would not suggest this, but the new has some factory stuff on it.
Then I would apply a single coat of quality primer on the surface like Zinser BIN. Then apply your finish coat of a quality "paint dealer" paint.