When 3D printing with the Inventure, you can use filaments either in cartridges or on spools. If your filament is enclosed in a cartridge, but you want to use a spool, you have to disassemble the cartridge and separate the spool from the cartridge. Follow the steps from this manual to see how to properly open the cartridge casing and remove the spool.
Remember that if you want to use a spool, you need a special spool holder. More details are available here.