Tomatoes in grow bags

I have prepared the growbag, got the canes out and decided to try this ring method.  I have cut the bottoms out of three flower pots.  Now I think I just stand these on the bag holes with the plants in, although they are posti-plugs.  Then I gradually fill with soil.  Is peat free compost ok.    Thanks for any advice.  Mrs Bouquet

Be very careful with watering, as the growbags can fill up with water. When I used them last, I prodded some holes in the bags about an inch up from the bottom so any excess could drain away.

They will need feeding regularly once they start getting tall. Good luck!