For short term, MY OPINION - less than 2 weeks max, the article above works. However if it's looking longer, you'll really need to look at longer term solutions. The .mil has solutions that way.
.mil solution download:
http://www.marines.mil/Portals/59/Publications/MCRP%203-40A.4%20Formerly%20MCRP%204-11.1D.pdf?ver=2017-10-10-094644-930
It is the following manual:
FM 21-10
MCRP 3-40A.4
(Formerly MCRP 4-11.1D)
Field Hygiene and Sanitation
Starting page A-39 thru A-43 (pages 133-137 of the pdf) you'll find pictures and such on how to make field type toilets.
It's fundamental knowledge has not changed much since I was first exposed to it ( 1971 - back when I was a .mil Medic )
I have this pdf and ran it thru a pdf to Word converter and am in process of re-formatting for better reading. Be happy to email either or both to anyone,