This is the main window, or form in MyFFshell. It is like a terminal talking to your Micro Control Unit (MCU).
The terminal window also acts like a command line history, and you can edit and reuse previous commands.
Note that character input from the keyboard is only send to the MCU, when you hit the Enter key!
Only exception is the ESCape key, which e.g. might be usefull if your program has a key? word, looking for operator action.

From this terminal window, you can open 3 more windows:
The SOURCEFILE window, the LOG window and finally the HELP window.
It is also from this window you initially set the Serial Communication parameters.
Under the File menu you can save the current communication settings. They will then be used at the next start of MyFFshell.

Note the big button: Sourcefile window
which makes it faster to get to that important window - faster than via the Menu, if you use a mouse.

It is also from the terminal/main window you open and close the communication with your MCU.
You can choose an "End of Line delay", but it should not be nessesary!
When lines are uploaded to the MCU from the Sourcefile windows, MyFFshell waits for a Carriage Return (CR) from the MCU, before sending the next line.