The various gods you collect can have a "tap" skill that is explained in their description details. After the about the third battle you will be able to use lightning bolts, which act as energy for skills and other things. To use a god's skill, tap them and it will expend one lightning bolt. Chests When chest tiles appear, you can open them by matching normally, or spending a lightning bolt. Chests contain equipment for your existing gods to make them stronger, or new gods. If you cannot make a match within a reasonable time to open a chest, just use a lightning bolt.