@georgia already shared some rune info.
Ooh runes, love them 
. Lots here, type in runes in the search or click on my profile and scroll through the posts I’ve done. Here’s a master post on the Norse too.
As far as altars are concerned. If you like runes, they are also your altar to the gods.
Get your little bag of wooden/crystal runes.
Put them in a circle.
Put a candle in the middle.
No need to cleanse, incense or anything, the runes do all that.
And connect with spirit, do your spell whatever.
And if you don’t have any physical runes, grab a bit of chalk and draw them in a circle instead. The chalk version is sometimes better as you can make a big circle so you can sit in it rather than just in front of it.
You can also use stones, twigs, lego, marbles literally anything that can either be drawn on, or put in the shape of each rune. They’re versatile and creative.
Skal 