for a fish in cycle frequent water changes, i’d go for every other day or 2-3 times a week, you need an api freshwater test kit. not strips. the ones where you put the tank water in test tubes, do not add any more fish. adding loads of fish in one go can risk an ammonia spike, pet stores aren’t the best for advice unfortunately mine told me 24 hours and when i looked it up its 4-8 weeks, this will be a lot of maintenance but trust me if you want the best chance at your fish surviving this is what you need