cable clips

Hi everyone! Newbie here, still getting to grips with DIY! I have an ethernet cable that I need to pass from one side of the room to the other. I read about cable clips and trunking, but there is a balcony door on the side of the room I need to run the cable through. The first picture attached...

With the 18th edition (don't have a copy yet), what applications can you still use conventional plastic cable clips? Do you have to use metallic cable clips holding cables on to joists in the void between ceilings and the floor above, and how about attic spaces? Regards: Elliott.