Sorry, i forgot about that bit. You need to remove the front panel and remove the 5.25 in plate.
Check out this link.
Fractal Design Define R2 - reviewed by MetkuMods - Because you love your hardware!
They say you need to press the plastic pegs on the inside of the case to get them out, then the front panel should slide off. After that the standard front cover plate has 2 tabs on either side that you can push in and the plate will pop out.
As to installing from the inside or the outside, its up to you; either works, but when you get your motherboard+cooler in, it'll be quite tricky to go from the inside out, if its possible at all.