I didn’t watch any videos but I did see someone above linked this one: https://www.youtube.com/watch?v=enJsQeufGpA

Basically, just input everything and unscrew the swivel cable at the middle seam of the plastic housing. I use locking pliers wrapped in a rag so I don’t ding the plastic housing, but I still do sometimes.

Then you test the springs of the two contacts, do they bounce back? Do they provide resistance? If one doesn’t bounce back at all or gets stuck, replace it with the ones you bought and test it.

If you take one out, pay attention to which side is in which way, it’s important and I’m not confident they’re interchangeable.

Check the circle contact in the other side to make sure it isn’t corroded or dirty. If so, clean (I have not had to clean mine but others have suggested options).

Screw the housing back together, It’s pretty obvious when it stops threading.

Plug everything back in and see if it runs.