There are various versions of the user manual that have slightly different commands, such as A and H for arming and disarming (as you found out). The manual I have uploaded is as close to my original paper copy as I could find, however, it is slightly different but for most things it should be ok.
Risco_Agility_User_Manual.pdf
Heres a link I found that matches my manual dated 2012, the previous one is 2009:
https://irp-cdn.multiscreensite.com/a1d869e9/files/uploaded/Agility-2-Full-User-Manual-UK1.pdf