so,when I give the order to a corp commander to organize the units in double line and the corp in mass order,the regiments will be deployed in double line.But will the divisions and brigades within the Corps be organized in double line or massed?
There are 4 formations for corps : battle, echelon right in front or left in front, chessboard. The only case a corp is form in 3 lines deep is in chessboard formation. For the other formation, it depends on the % of reserve you chose.
If you organize a corp composed by 17 units (regiments or arty cies) in battle fomation, for example and you decide to have a reserve of 50% : there will be 9 units in first line and 8 in second. If you don't want any units in reserve, there will be 17 units in first line and for 30% there will be 12 in first line and 5 in second.
Columns, line, mixed order are units formations (régiments).
So you have to define corps formations (battle, echelon or chessboard) and units formations (column, line, mixed order).