I designed this ender 5 spool holder for my Ender 5 with direct drive extruder.

It sits in the back by the y-stepper motor and it conveniently slides into the frame so you would only need:

2 screws and 2 t nuts that already came with your original extruder.
You would also need 4 size 8- ½ Robertson screws to mount the spool tower to the frame mount.

Ideally you would reuse the original roller that came with the original spool holder and the nut that tightens it.

Lastly to keep the spool from sliding off, you should print the end cap that slides nicely on to the oem roller.

This spool holder is very sturdy and it works great. 
Below I included files for all 3 parts separately so you can pick if you need all of it or just one of them.