You should early on get used to using commands instead of F1 – F12.
A byobu command begins with Ctrl+a followed by a character.

If you press ctrl+a for the first time you will be asked wether you want to work in the screen or emacs mode.

This setting defines what escape sequence you want to use.
I use screen, so Ctrl+a.
If you use the Emacs setting it will be Ctrl+b to send a command and Strg+a jumps to the beginning of a line (as it usually would).

Once you made that choice you can start using Ctrl+a (or Ctrl+b) to send commands.
To do this press Ctrl+a, then release all key and then press the command key.

A new window for example gets created using Ctrl+a —> c

You might be thinking that this is way more complicated then just pressing F2 and you might be right about that.
However, once you want to send a command multiple nesting layers deep you will be reliant upon this method.
So lern it the right way from the get go.

Also after a short learning period you do not want to go back to using the clonky F-Key method any more.
Trust me.

Here are some of the commands that I use the most.

Escape Sequence Command Function
Ctrl+a ? Lists all commands
Ctrl+a c Creates a new window
Ctrl+a k Closes (kill) a windows
Ctrl+a <Number> Jumps to the window <Number>
Ctrl+a | Horizontally splits the shell
Ctrl+a % Vertically spits the shell
Ctrl+a , Renames the window