You'll need to print the base and two of the vertical holders. I printed all three at once on my Ender with no supports. You'll need to glue the two holders into the base.
I recommend printing the vertical holders on their side. Cura can also easily scale the vertical holders to be taller or shorter.
There are holes on the corners if you want to use them to secure to another base.
WARNING: Use safely and try not to start a fire.
The author marked this model as their own original creation.