They're basically constructed of a two part shell, so you find all the screws, remove them, and take the two halves apart. Since your camera is designed with a small dome to house all the external switches you would need to remove the back half of the body shell first to see how the switches can be accessed.
It's possible at this point that you'll need to remove the innards from the front body half shell to get at the On-Off switch. The switch itself will be on the main PCB (Printed Circuit Board), as the external blue part is just a flexible cover.
There are lots of things that can fly out or drop silently to the floor when doing all this, plus if the switch itself is bad you'll need a replacement part, and some soldering skills.
These types of cameras were designed for ease of assembly on a line with a minimum of tools, not for servicing later on. That's why they were sold in the consumer market. The philosophy was, when you have totally consumed the camera, it's time to chuck it and get another one. Repair costs were usually way more than the cameras were worth, or about the same cost of a new and improved model.
PF