Running old games on new OS’s is a constant challenge. This is the list of places to go and things to download which made Command and Conquer: The First Decade work for me.
Most of it works right out of the gate, however Tiberium Sun notably needed a few patches.
First, get TFD and extract the ISO. Open up the ISO itself and grab the Px777 directory and extract it somewhere. It will have a keygen you’ll need - but don’t assume the cracks work (they don’t on win10).
Mount the iso, install as usual, use the keygen to generate like 7 keys (one for each game).
At this point, you can run a few of the games (including the original and renegade). Notably, I wanted to play Tiberian Sun, which gave me "Insert the DVD" errors (even with the DVD mounted), which appears to be a result of changing SecuROM in win10. So even if you have the iso mounted, it won’t work. Worse, the cracks are old and complain about DLL errors if you try to use them.
I had to do three things to get this to work, it’s possible that the order i tried them is wrong, and you don’t need all three. I first grapped the ddwrapper and put it into the installation directory. I understand that this helps with some black-screen movies. Second, i got the unofficial 103-rev4 and installed that (which changed the icon for the game, fun fact). However, I still had DLL errors. So i finally got the Windows 8 compilation patch (which I fully expect will probably fix everything from the get-go).
After that last step, you’ll have a different executable that runs the game. A shortcut ought to be on your desktop, but you need to run TSLauncher.exe, not game.exe.
Finally, when running Tiberian Sun, I cranked the resolution way too high. The game is old enough that the resolution you play at changes the visible play area. So if you have a 2k monitor, everything is wicked tiny. I had to bring it down to 720p; everything else made all the units too tiny, and too much visible (but useless) area.