You get a program that can open and extract RAR files, such as
WinRAR or
PowerArchiver. Open the archive after it's downloaded. and input the password given by Rifke (bga`F$E#aV~^C^Y) and the RAR should open up. Extract the files to wherever, input password again if needed. Then, run the executable of which you want to use (stbeditor.exe or stleditor.exe) then go to File > Open and navigate to the STB/STL you want to open and read/edit.
If you have no STBs or STLs, grab VfsNextGen from
http://rosefiles.com/files/VfsNextGen.zip and put it in your Rose Online Evolution folder. Run it and it will create a tree view of all the files inside the VFS files. The STBs and STLs are located in /3DDATA/STB/. Click the file to extract and then right click > Extract item and put it where you want it.