the best way is to read the relevant literature with the paint.
Generally if the wall is sound, previously painted areas , if any are also
sound and free from growth such as moss then several coats of the masonry
paint is the best. By several I mean whatever the manufacturer recommends
depending on the colour chosen and what the colour is you are painting over.
Stabiliser is only needed when the surface you are applying it to is poo,
flaking or very dusty. On a new rendered surface I would just use 2 (or
perhaps 3) coats of a quality masonry paint