Well, before I go into what to do during a blackout, know that you don’t fix fuses during a blackout. A fuse will blow when you’ve overloaded it (like when you have too many things plugged in & try to turn on the hairdryer). If there’s a blackout, there’s no energy coming into the house, so there’s no way to overload a fuse.
Unless your house is a million years old, you probably don’t need to change a fuse, but rather, reset it. If you go down to your fuse box, you’ll see all the fuses switched to the same side. If a fuse as been blown, you’ll see that it’s not 100% to the side that it is supposed to be. It’ll be somewhere like 25% of the way in the opposite direction. What you need to do is flip it all the way to the far end (to turn it off completely), then all the way to the side it’s supposed to be on (most likely the left). That will reset the fuse and you’ll be good to go.
In terms of what to do in a blackout, you really just need to wait for the power to come back on. Unplug any appliances that were in use when the power went out so that they don’t get overloaded when the electricity comes back. Turn off any unnecessary or sensitive electronics (i.e. your computer). Make sure at least one light is still switched to the “on” position so you know when the power comes back. Keep your fridge closed as much as possible. During shorter power outages, the insulation will keep your food cold, but only if you keep the fucking door shut. If your power is out for days, though, you will need to get rid of everything in your fridge and freezer because that shit is done for.