Odin runs on a PC under Windows. (Saying you downloaded it to an SD card made me think you were trying to run it on your tablet.)
Try to use the Search function on the site. There's probably a thread on rooting the S7 Edge. There's definitely a thread on Magisk.
Here are the Magisk installation instructions.
Don't start with "I don't know anything, somebody tell me how." Read a lot of posts, at least learn some words.
Was I wrong to assume you want to root your tablet? What made you decide you wanted Odin? What is stopping you from Googling "unlock"?
Before you do anything destructive, find and download a copy of your current ROM, so you'll be in a position to recover. You can test burning a ROM without unlocking the bootloader, as long as it is an official Samsung-packaged ROM.
Good luck.