Side note; I'm using my OC Crimson as an example of a ghost like character.

First, you go to hide (which is in the "props/others" category)

Second, you turn off "Display Thigh, Display Back Thigh, Display Foot, Display back foot".

Third, go the "belt/skirt" in the "clothes" category)

Last, go to the 6/7 and pick the ghost like body.

Mintstripe9
(Hope this helps with making your OC.)