Some of them directly inhibit candida like DDS-1 or S. boulardii, but otherwise just take as many strains as you can in significant does (20bn CFUs+). They’re able to pass on genes to your indigenous bacteria, so the more strains you have contact with, the more potentially helpful genes get passed along. For example, consuming yoghurt or kefir can lead to lactose tolerance after lactose-digesting genes are transferred. It only takes a couple of weeks for this to happen, so change brands every month if you feel like it. Homemade kefir is best as a “staple” source. Unfortunately, if you’re missing enough indigenous bacteria, you’ll need to find a way of replacing them for a full cure.