Re: DC switch panel
Not always push-and-twist. If they are the standard "Sea Dog" type panel, get your reading glasses and take a squint at the left side of the "FUSE" buttons. You will see a small tab in a slot on the left side of each.
Carefully, because old plastic can be brittle and break, press in the small tab with a toothpick or paper clip or small screwdriver. Now the red button will fly out and a small spring will get lost--unless they stay attached to the standard glass fuse that is inside.
Pull the red button out, with fuse attached. Replace fuse, press it all back in place, the tab will latch in again by itself, unless it was old and brittle and broke off. In which case, you have to buy a new fuse panel because they don't sell just the plastic bits.
Or for the price of postage, I'll let you have an old panel with four still good, two with tabs popped off.
Those are the older standard "automotive" type glass fuses in there. PITA to replace them that way, but I suspect using those pop-tabs instead of conventional screw-down fuse holders probably save them two bucks on the price of the panel. Or it prevents gremlins from stealing your fuses.