That looks great - I think it is as precise as can be under the circumstances.
A few typos:
"As we already outlined in section 4.1.5, the time to comple an order" - 'comple' should be 'complete'
"A Supporting Corps may be situated behind or to either side fo the Main Corps." - 'fo' should be 'of'
"He knows the strength of the Main Corp" - 'Main Corp' should be 'Main Corps'
The only other nitpicking thing is the sentence: "If a Main Corps is retreating, for example, its order will automatically transfer to the Supporting Corps in the rear, or, if none is present, to the strongest Supporting Corps on the flanks."
Previously, the term 'to the side' was used rather than 'flank'. Also, using the tense "is retreating" might make it sound like the supporting corps are also retreating - in effect, as soon as a Main Corps starts to retreat, the order will transfer. A possible change:
'If a Main Corps retreats, for example, its order will automatically transfer to the Supporting Corps in the rear, or, if none is present, to the strongest Supporting Corps to its side.