I attempted my install last night, and had the same issue with the support brace - I wasn't sure where to attach it. After looking at pictures I realized the short part of the elbow attached to the stock intake tube, but I was unable to get it on as easy as the other side - I'll try some soapy water when I redo it on Saturday.
I ended up putting the stock intake back on, which was no big deal since i have to install a DHM symposer delete on Saturday, and it all needs to come back out anyway. I didin't realize how much stuff needs to come out for that (battery, battery tray) and I didn't have time to do it last night lol.
For the hose that goes into the tube (with the green clamp) you can probably get a small hose clamp to hold it on.