I managed to do this at 11 years old. I'm 15 now, and adding games like crazy!
I guarantee you this is an easy guide :-D
Step 1: Make sure you have a nintendo DS
Mine has a Disney Gamer sticker on it from one of my sister's games lol.
Step 2: Make sure you have The Day of the Tentacle disk
Step 3: Buy an R4DS cartridge.
When you buy it, you will now have the Cartridge, a blue case for it, and a USB drive with a MicroSD slot.
Correct? Let's move on then.
Step 4: Buy a MicroSD chip.
SLOT IT IN THE USB DRIVE BEFORE PROCEEDING WITH NEXT STEP.
done that? Okay, let's go...
Step 5: Donwload the kernal and Scummvm on to the flash drive (with microsd chip inside it)
Step 6: Extracting the Kernal
(It's just to make everything neater when extracting)
download the flash drive kernal on to your desktop: http://download.r4ds.me/v1.18/R4_v1.18_English.zip
(This enables the flash drive to work properly.)
Place the kernal you have just downloaded into the 'ds kernal' folder you have just created.
Right click the Kernal 1.18 and select 'extract here'.
Step 7: Installing SCUMMVM
Download SCUMMVM into the 'SCUMMVM' folder you have just created. Extract again.
LINK FOR SCUMMVM (DS): http://prdownloads.sourceforge.net/scummvm/scummvm-1.2.1-ds.zip?download
Step 8: Copy the SCUMMVM folder and KERNAL folder onto the USB
Once copied, open up My Computer, and Paste them into the Removable Disk.