Ok so, take water essence for example. It says it can combine with other items. How exactly are you supposed to do that? Please share your answers!
Are you referring to the buddy box items or the Avatar items? Either way, they combine automatically- you just need the correct number of items. There is a fantastic buddy box thread, same with the Avatar items thread. They will tell you exactly what you need. ? I'm sure some lovely folk will add the link for you (I dunno how. ?)