5.1: Take drill and increase diameter of hole on frame plate between chassis uprights where the On/Off Killswitch is mounted.
Before Immediately going too big, you’ll want to go a notch or two and try fitting and work from there so you don’t oversize the hole more than it needs to be.
5.2: Install On/Off Switch and secure to frame.
You’ll use a 14mm wrench to secure the nut on outside of toggle switch. Alternatively you can use a smaller type adjustable wrench as well.
For a visual demonstration, you can refer to the following video:
