Since you run DOSBox on the TryHackMe VM you will need to use the key right above (or next to depending on the keyboard) enter (in the German keyboard is the # character).
But I just realised that depends on the way you connect to the TryHackMe VM. So normally to print the \ character using the German keyboard you need to press Alt Gr + ß. But in this case it doesn't work for some reason, so you need to press ctrl + alt + 92 (you need to keep ctrl + alt pressed while typing 92.)
