Smudging is fairly easy.
You will want to open your windows a little bit so that negative energy can leave the space and also so that you can move the air. After I sage/smudge it gets cloudy so keeping the windows open helps clear this afterwards.
You will put the sage on the shell or a ceramic plate, light the sage on fire and let it burn a bit. It usually goes out on its own but leaves an ember. These embers are what produce the smoke for smudging.
Set an intention for your clearing. I usually say something like “please clear this energy for our highest good and replace any negative or stagnant energy with love and healing energy”.
Think this intention to yourself while you work your way around your home. Making sure you smudge in all of the corners, doorways and around windows.
Make sure the smoke from the sage goes from the place you hold it, all the way up to the ceiling, or from the floor-ish to the ceiling.
If the smoke kind of “clusters” where it is, set your intention stronger and move the smoke a little more heavily to move the energy. This is just energy that is either negative or stagnant and it might need a little extra boost.
After you do the whole area, you are done. The sage will burn out on its own. Leave it somewhere safe, and on something like a shell or ceramic so it doesn’t cause a fire.
If the smoke isn’t being produced as much, you can re-light it on fire to get the embers lit more. Then I open all the windows and let the air flow free and the house will likely “feel” a lot better after you are done.
Additionally, you can set whatever intention you want. You can call guides, angels and other positive beings in to help. You can also add some Reiki in there, if you are attuned to it. And for in between smudging (because it can take awhile) they make sage smudge spray now and you can spray it around areas that you “feel” intuitively need it.