Just like we did with Carbon Steel. This video covers some good tips on how to build muscle memory without filler metal before you do the real thing.
Aluminum will often crack when welded without filler metal but dont be too concerned about that right now....this is a learning exercise before progressing to adding filler metal.
Its also a good practice to use 2 separate plates so that one of them can be cooling off while you practice on the other.
.125" 3.2MM THICK aluminum
3/32" 2% lanthanated electrode
#6 cup with 12-15 cfh argon gas