I apologize for the stupid question. I installed arm9loaderhax (https://github.com/Plailect/Guide/wiki). It works fine, but I can not use another SD-card. Even if I have copied all the files and folders to another SD, 3ds is not started. The only way - to write the ISO image. What have I done...
One of the sites that weren't blocked on the school's network was some file uploading sites. I would upload some games, write down the URL and take it to school one day.
my school has a chrome extension called light speed filter agent and it legit blocks YouTube pfps since the file cdn(I think aka yt3.ggpht.com) is classed as mature
It was easy to bypass some of the restrictions, as one of the admins left a registry key in the administrative shares drive, which allowed me to get around the blocking of some sites.