Carefully read the instructions on the bottles and shake vigorously for accurate results, this is especially the case for nitrate bottle two.
Make sure you are not over-feeding your frogs, remove uneaten food straight away so it doesn't have time to collect under ornaments.
African dwarf frogs can adapt to a fairly wide range of pH levels, what is most important is that the pH levels remain stable, it is the swings and crashes that are most dangerous.
Use Seachem Stability, Tetra SafeStart or equivalent when attempting to cycle your tank, many people find it speeds up the process.
Make sure that you have a filter that can adequately handle the bioload of your frogs. Avoid massive water changes over 50%, this can crash your cycle. Don't over-clean/rinse your filter, this can also crash your cycle.
The African Dwarf Frog community has a wealth of experience and can advise on things such as PH swings, cycling, water hardness, infections and tank setup! Check out the facebook group HERE