You will need to install several progams before you can start the installation.
-Rufus, to write the disk image to an media.
-gnupg, to unencrypt the files.
-The disk image
Unencrypting the image
For security purposes the image is encrypted with GNU Privacy Guard, you can unencrypt it with https://www.gnupg.org/download/, if you do not know how to compile you own progams from source i recomend that you install the binary release for you operating system, fo windows you will need this file. After it is installed it depends in you system on how to continue.
Windows: manual
MacOS: lorem ipsum
Linux: If you are a linux user you can probaly figure this out yourself.
Now that you have an debian-robotica.img file you can write this to an media using rufus by selecting the media you want it burned to in the decice section. You can select the .IMG file using the select button next to the boot selection. Set the perscistent partition size to the maximum posible, and for target system select BIOS or UEFI. For the file system you must select NTFS. And leave the cluster size at default.
In order to boot the system you will need to turn of the device where you will run it on. After that you will need to go into you system's boot menu. For the laptops at school you will need to enter it with this manual. If you want to do it via another device you will need to search for an manual yourself.