The first place you may want to check is www.asha.org
, the website of the American Speech-Language Hearing Association. You can try searching on that site using key words like cochlear implant, aural rehabilitation, and hearing loss. They have a lot of great info on communication & communication disorders for the general public, but you may have to search through the site a little to find it.
I don't know what your background is or how much experience you have with kids with cochlear implants. I'm a speech-language pathologist and I've worked with a handful of kids with implants. That is to say, it's not a specialty of mine but I know a few things anyway. What I noticed especially is that 5 years status post implantation can mean a lot of different things. Some kids at that stage have age-appropriate communication skills (often a mix of manual and oral language), and other kids are still barely getting any benefit from the implant. It depends on cognitive factors, health, age of implantation, parental support, and teacher/therapist skill.
The most basic thing you need to do is get someone to teach you how to check if the implant is working. Those things go through batteries like crazy. Check the batteries at least daily. Check to see that it's in place and turned on. Check to make sure the FM system is on the right channel, if you're using a multi-channel one. And make sure your FM unit is also turned on and full of batteries.
Next, make friends with the child's speech-language pathologist. If there are still language issues, and the child is in the USA, then the child will certainly be getting language therapy. Find out who is giving the therapy, what the goals are, what the child's level of functioning is (strengths, weaknesses), and what tips the SLP has for bringing out the best in the child.
In addition, as with any child with hearing loss, you need to make the classroom acoustically friendly. Get area rugs and curtains. Close windows if there's any noise outside. Sit the child away from heaters or AC units. Close the door. Put cut-open tennis balls on the legs of chairs that scrape noisily. Always face the child directly when speaking (don't talk to the blackboard, stand in the shadows, or show your profile only). In general, try to decrease background noise as much as possible. This will actually help all students hear you better, and is just generally a good thing to do.
Feel free to PM me with any specific questions that arise. I may not know all the answers, but I can find them pretty easily.