First thing I recommend is take your working, STOCK, working Install of the game and make copies of it. This way you will not need to re-install the game, and two you can have numerous mods installed (I have over 15 versions of the game installed on my computer, most used for testing, but I also have a copy that is just Revenge of the Jastas, a few that are REDUX, one that is Hells Angels, and so on.)
Campaign Manager only works with Win XP, and at 32 bit only I believe. You can use a Virtual Machine running WinXP to run Campaign Manager
Now, you could do the file swapping manually. If you look in the Date folder, you will see numerous folders with what seems to be a random series of numbers. These numbers are not random, they are dates. The first to digits is the year, the second set of two is the month and the last set of two is the day.
For example, folder 160815 is for 1916 (16) August (08) Fifteenth day (15)
The first thing is to know the date your pilot is flying. Find the folder that day falls in. For example, August 15th 1916 to August 31, 1916 would use folder 160815.
Then take the contents and copy them. The contents, not the folder itself, and then paste the contents into the simpatch folder. Allow the files in the Simpatch folder to be overwritten.
Then play the game, but remember to change Simpatch's files from another folder when the date changes to a new folder. If using 160815, you would need to change the folder out again when the date becomes Sept. 1st, 1916 (folder 160901)
Mods such as Hells Angels and Revenge of the Jastas does not use date changes, so once the mod is installed, you do not need to do anything else for the gameplay.
Most of my experience is with Revenge of the Jastas, and for RotJ, all of the Mod's files go into Simpatch.
Also, for the best graphics, look for Capt. Darwin's FCJCP (Full Covered Jacket Control Panel) This utility can let you push the graphics of the game higher, including setting the resolution to match your monitor. RB3D stock will only give a Maximum of 1024x768, but with FCJCP I fly with an actual in game resolution of 1280x1024