Step by step guide to getting those new dual screen mods working
Since the dual screen patches have been coming out, plenty of people are complaining about not being able to straight get them to download so I'll give you a guide.
You will need your own ROM. This will need to be done on your phone or PC. To do this you need to GOOGLE THE GAMES NAME + ROM. Download a base ROM. SNES and GBAs are easy to come by but if you need a DS one then VIMMs LAIR is your answer.
Open up FTPD on your 3ds and make sure you are connected to the same network as your PC or phone. You can hotspot to your phone to achieve this too. Get your IP which will be something like X.X.X.X:5000. If you need more help on this step then follow this guide.
Go to your PC and open your File Explorer and in the address bar type: ftp://X.X.X.X:5000 and hit enter, you are now connected to your 3ds. If you are using a github link, create whatever folder it is you need in the 3ds/ folder. For example https://github.com/EstebanPdN/zelda-alttp-3ds the Link To the Past mod needs you to create sdmc:/3ds/Zelda 3DS/ you can do this either by PC or by the FBI Launcher on your 3ds, both are fine. You already have the 3ds folder so you are just creating a new folder!
Now go to your PC or mobile and move the ROM into that folder you just created. Once it's moved then close FTPD and open FBI.
Go to remote install on FBI and go to the Github of whatever mod you are looking at. I'll use the Link To The Past one again. https://github.com/EstebanPdN/zelda-alttp-3ds/releases/tag/v2.9
Scan and install.
Go back to the homescreen and you'll have a new package waiting for you.
Enjoy your game!
This can all be done with your phone too, on Android I use X-Plore to connect to the FTP server and move the rom over to the 3ds folder that we needed. If you have any other questions I'll try to answer it for you.