Gypsum plaster / rhinolite should be lightly sanded down with either steel wool or very fine grit sandpaper (P220).
Dusted off with a cloth and primed with one coat Versus Plaster Primer.
Once completely dry (See table for approx. dying times and spread rates), then finish with 2 coats of the desired VERSUS FINISHING COATS**/ VERSUS PREMIUM / ECONOMY PAINT / EXCLUSIVE WALL COATING RANGE.