Download DISKBOOT.BIN from
here.
If you want to boot with CHDK, just temporarily rename this file and change original CHDK back to DISKBOOT.BIN.
You can easily switch between both versions.
The only file you need from Common_folders.zip is time_lapse.bas in the Scripts folder.
Copy to the scripts folder on your card, enter ALT mode and press the shutter button.
After a ten second delay it will take three photos at ten second interval.
Change the number of photos and interval or for your model aeroplane set to endless shooting.
David