Sharp 7900 black copies and low developer

Question

First the copier started making more and more totally black copies, and the low devloper warning light was on. Toner had spilled inside the copier. I cleaned and vacuumed all of the excess toner.

Is developer and toner the same thing? There are separate warning lights for each. I have puechased a new toner cartirdge and a bag of developer. I know how to install the toner cartridge. What do I do with the developer?