Here's the US Army's 1947 manual on how to execute people. I like this part:
f. Upon pronouncement of the death of the prisoner by the medical officer, the execution party will proceed to the racks from which the rifles were originally obtained, and replace the rifles in the racks at random. The execution party will then be dismissed.
g. The escort, with the band playing a lively air, will return to their parade ground and be dismissed.