How do i set ring volume on a binatone veva 1200

If the serial number under the base starts with "VT" under the base unit:
Press OK, press the arrow down to HS Settings, press OK, press the arrow down to Ring Setup, press OK, press the arrow down to RING Volume, press OK then use the arrow keys to set desired volume, then press OK. You may want to change the volume on the base too, in that case, the same instructions but instead of "HS Settings" go to "BS Settings".

If the serial starts with a "B":

Press Menu, press the arrow down twice to HS Ringer, press OK, press OK again, use the arrow keys up/down to select required volume then press OK.