Soly

I had the same issues as you as I just started looking into creating skins for aurora. No one would give me an exact answer of where or what your looking for it was basically Google it for your self. All I found was talk about it but no mentions of what xuitool is apart of. All the devs would say its apart of the SDK, XDK & you need it etc. At the end of all this Bullshit I got sent around to look for was a needle in the hay stack. But I found out what xuitool is & apart of as I couldn't understand why the devs on here wouldn't tell me. Sorry for the rant. But here we go.

Its 360 Neighborhood. Everything like Xuitool is apart of this. I dont know why the Devs dont just say you need Neighborhood? So just download the latest or any 360 Neighborhood as all the files needed are in neighborhood to open .xui files 

You will need XZPTOOL to unpack & repack the skin.xzp you are going to build a skin from. Use the Default.xzp of Aurora is a good start or someone else's custom.xzp skin as I used someone else's skin as you get an idea of how & where they made changes to that skin etc.

Swizzys DDSCONVERTOR & Metagenerator read up on it. You will know why.

AuroraElements extensions. Found on Phoenix.xboxunity.net just keep scrolling down until you see the link to download it. You add it into xuitool extensions ect. It helps prevent the .xui files for Aurora to open. Or the devs call .xui xur files etc

All this besides Neighborhood can be found on realmodscenes. Watch felidas tutorials as there basic but give ideas on how to use xuitool. He dont go into full detail but it gives you an idea. 

Just Google for neighborhood easily found.