On my machine, pressing Alt-B would first select the "Set a True/False (Boolean) Value", then pressing it again would select the "Begin a Conditional (If Statement) Block" action('s entry)
The command for the Set a True/False (Boolean) Value action could be something like
Press Left Alt+O keys and hold for 0,01 seconds and release
Press Left Alt+A keys and hold for 0,01 seconds and release
Press Left Alt+B keys and hold for 0,01 seconds and release
Press Enter key and hold for 0,01 seconds and release
And the one for the "Begin a Conditional (If Statement) Block" action could be something like
Press Left Alt+O keys and hold for 0,01 seconds and release
Press Left Alt+A keys and hold for 0,01 seconds and release
Press Left Alt+B keys and hold for 0,01 seconds and release
Press Left Alt+B keys and hold for 0,01 seconds and release
Press Enter key and hold for 0,01 seconds and release
Press Left Alt+S keys and hold for 0,01 seconds and release
(S to select "Single Condition")