I can remember digging in, in the German forests at night, and 'going for a walk with a spade'. The civil war encampments would be no different, except a lot more organised. Note - no overhead or side cover.
Latrines. Basically a deep trench with poles to sit on over it. Once full - or too smelly, a new one is dug.
There again, they didn't need to have anything to sit on
Levi Wood Baker,
History of the Ninth Massachusetts Battery. Lakeview Press: 1888 describes the practices at Union Fort Davis, a second line fort on the Jerusalem Plank Road:
Headquarters 1st Brigade, 3D Division, 5TH Army Corps. July 29, 1864.
General Orders. No. 17.
The following police and sanitary regulations for the command will be strictly carried out ....... The sink holes will be at least one hundred (100) yards from the fort, and will be from six (6) to eight (8) feet deep, four (4) feet wide and six (6) feet long. Every regiment will be furnished with boxes and barrels for each company, to hold dirt, slops, garbage, urine, etc. No refuse matter whatever will be thrown on the ground, but will be placed in the boxes and barrels, which will be emptied into the sink holes twice daily, viz. : between the hours of five (5) and six (6) o'clock in the morning, and six (6) and seven (7 ) in the evening. No officer or man will be allowed to urinate within the walls of the fort in the daytime. At night urinals may be used. Each regiment will have sinks dug at not less than one hundred (100) yards from the fort. These sinks will be at least twenty (20) feet in length, and will be properly fitted up and screened. A thin layer of dirt will be thrown into the sinks and sink holes every morning, until they are filled, when new ones will be dug. A sink for the exclusive use of officers of the brigade will be also furnished. The colonel commanding the brigade, knowing that all officers and men must see the necessity of a strict observance of the above regulations in the present crowded state of the command, expects prompt and cheerful compliance with all measures he may adopt to promote comfort, cleanliness, and prevent disease. This order will be read to each company in the command. By command of Col. Peter Lyle, commanding brigade, BYRON PORTER, Capt.& A.A.G. (pp129-130)