I don't have time to give a complete tutorial but the first thing you need to do is set your monitor size to something larger than 1024x768 to be able to see the entire cloud editor.
Then go File/Open Terrain and select the bitmap of the terrain you are working on – example MyTerrain\texsrc\MyTerrain.bmp Your map will then appear in the viewer.
On the left panel, add/edit cloud layers. You cannot see this panel if your screen size is too small.
Click File/Save Weather to save the cloud layer information to MyTerrain\MyTerrain.awa.
Copy this file into Aces High II\ahiiterr folder, launch AH2 and your terrain will have clouds without having to re-build your terrain. Once you get the clouds the way you want them, re-build your terrain and the awa file will then be included in the res file.
Play with it and see if you have any specific questions. GL
