Here are some helpful resources
Yamaha and Music EDnet have more information on choosing the right microphone. More on microphone recording patterns can be found at Townsend Labs and Gearank.
Practical Music Production has information about the importance of mic stands in studio set-ups, and Neuman can tell you all you need to know about Condenser mics.
Fender provides some useful information about feedback and reverb.
More on cables and sound equipment for the classroom from the TMEA.
If you're still confused about why you need to use the correct cable for each connection, SWAMP, (this one too), and No Treble can help you out. Gollihur Music will tell you more about the difference between Stereo TRS and Mono TR cables.
If you're trying to choose between a tube and solid state amp, this guide may be helpful. If you're thinking about amps for specific instruments, the HUB may be of use to you. If you want more information about how amps work check out ElectronicsTutorials.
Wired, No Film School, and The Black and Blue all provide more information and tutorials about cable rolling technique, including tutorials.
I highly recommend experimenting with the gear you have in your music classroom to better understand how it works. In creating this resource, I found experience to be the best tool for improving my tech skills and putting my new-found understanding into practice.