Ok, well seeing as I don't use Reinand, I'm going to be estimating this whole thing. But I'll try do a step by step tutorial that may help.
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Firstly, download this file: "
http://maxconsole.com/maxconsole_files/gateway/GW-ULTRA-3-7-1-BETA.zip" and extract it, and then extract the zip file inside the newly extracted Gateway file called "GW_3dsx.zip". Copy the (extracted) "GW" folder into the 3ds folder on the root of your SD Card for the 3DS (Where the homebrew apps are located).