He is 17 weeks (I think.... born 10th June).
I always freeze the veg in ice cube trays then once frozen I pop them out into plstic food bags and freeze them. At first you'll just need one cube at a time, and you can mix it with cooled boiled water and formula or some baby rice if you want to.
Best to start them on one flavour at a time but but as they eat more you can combine vegetables and use multiple cubes. I also used to use the frozen cubes with pureed chicken or fish, etc once weaning was well under way.
Whether it is the right thing to do is, I suppose, a matter of opinion. I firmly believe that it is the right thing for us as he is definitely hungry, doesn't have the reflex that makes him push all food out and doesn't seem satisfied with just formula any more. Also he is opening his mouth for the food.
Personally I think that there is only so much liquid that they can drink but I appreciate that all babies are different and, in particluar, it is different if you are bf as the 'richness' of bm adjusts over time whereas formula obviously stays the same.