What is the procedure to replace the reverse light switch on a 5spd?

What is your question?

My reverse lights have become 2nd/3rd gear lights. From what I can find online, this is a common problem on older Passports/Isuzu Rodeos (same car), and on the 3.2L with a 5spd manual like mine, the sensor is $10 and is located "on top of the transmission". Can't find any more info. Could I get a decent explanation of how to approach replacing this myself? It would be a shame to have to take it to a shop for a $10 switch if I can avoid it.