How to disassemble the timer in my toaster oven (tough mama brand)?

How to disassemble the timer in my toaster oven (tough mama brand)?

I was going to fix the timer of my toaster oven. But the problem is, I don’t know-how to detached it from the shell so I could fix it. Hoping someone out there could help me so that I can continue my learnings in the cooking of different western foods. Thanks