Starting Crafty can vary greatly depending on your systems operating system and setup. However, these are the normal ways:
After downloading and extracting crafty, double click run_crafty.bat in the folder. Crafty is required to run from the same folder as it’s needed libraries and other resources. This batch file will automatically CD into the correct directory (crafty) and run crafty.exe. If you wish, you can do this yourself via a command line interface.
Things can vary greatly on Linux, some people love Screen, myself, I love Tmux and thus, this guide will use tmux. From a terminal window type “tmux” and press enter. You will now see a terminal interface, but you are inside the tmux server. CD into the directory where the crafty repository has been cloned to (example: /var/opt/minecraft/crafty/web-crafty). Now run ./run_crafty.sh from Tmux. Crafty will launch. Once Crafty is finished launching, you can then “detach” it by pressing ctl+b and then d to detach the window. To re-attach the window type tmux attach 0. You can read more about tmux here