As far as ScummVM - each game requires a specific set of files in their own folder for each game (these can't be compressed into a single .ZIP or .RAR file). To keep them organized, it's best to put them all under another directory, for example, "Games". Then you'll have to add each game to the ScummVM launcher menu.
Step-by-step:
1. Create a folder to store all your ScummVM games. I find it best to just create a folder named 'Games' inside the ScummVM folder on your SD card, since that's the first place ScummVM goes to when you click 'Add Game' on the launcher menu.
2. Inside your new folder, create a folder for each game you have data files for. The data files required for each game are on the ScummVM wiki
here.
3. Run ScummVM on your Caanoo. After it loads, you'll be looking at an empty menu with buttons on the bottom. Tap 'Add Game...', then move to your games directory (double-tap a folder to name to open it). Then select a directory with the datafiles inside, and tap 'Choose'. Don't open the directory before you tap 'Choose', otherwise you'll be looking at the datafiles, and ScummVM won't know what you're trying to 'Choose'.
4. Repeat for all your games.