Proper way to create a cube dropper
I'd like to also suggest building your own cube dropper instance. It was the second thing I did whilst learning (the first being to design my own elevator - which has been through many many changes). I learned alot about how to manipulate prop_dymnamics, env_entity_makers, point_templates, "skinning" a prop through relays, I/O logics, drop distances/timings, the effect of a well placed cubemap and filters and triggers and func_instance_proxy 's and relays etc. The "simple" cube dropper is a great learning experience. Later because you know EXACTLY how it works (you built it) you can turn it into a "multiple style" cube dropper. Have it open with nothing coming out. Make it a paint dropper. Add in a standard length of vactube - with a bend (and push triggers if you must! ).
Also mapping with optimising in mind from the start is a good idea. There is a really good tutorial for this on interlopers here). Having just hit the wonderful "too many edicts" problem/bug in a map I'm making I'm glad I had already been following/thinking about optimisation and that I built most of my instances for "everyday" things myself, from scratch. I knew exactly where to cut the fat (with a gentle push in the right direction from LPFreaky90 
) You will benefit from it in the long run when your projects get ambitious !
Interesting! I will try to build my own cube dropper then, perhaps. I've been trying to find a good tutorial on how to build your own cube dropper but without success. Do any of you have a direct link to share? Thanks again!
I was going to type a whole thing here about not getting bogged down with details so early on, but if you're the kind of person who likes to experiment and take things apart, then perhaps this is what you should be doing
IMO the best way to create a variation of a standard instance, is to just open up that standard instance and see how it works, then base your own version on that. You will also learn a lot about entity logic and I/O in the process, which is very valuable.
Other Portal 2 maps: Medusa Glare
Portal 1 maps: Try Anything Twice | Manic Mechanic
I've been trying to but I don't understand all the entities, such as proxies for instance. How did you guys learn to create cube droppers? Youtube?
You'll learn the entitys by time. Nobody understands all entitys when hes starting with hammer.
Reading sites on the VDC, watching some tutorials, or asking on twp (which i would do at last), helps understanding entitys and how that all works.
Oh, and a Func_instance_io_proxy is used for Instances