need help on trimming the claws

[old geezer]

.. not sure when it's decided that the claws are too long--- my birds are 1 1/4 " length maybe a tad more ??? ?..sometime it looks like they are twisted to the side when they are on the roost board---but i'am a worry wort when it comes to my pets and want them to feel good an be happy--what is the desired length---the breeds are spec sussex---slw--buff orps ,rd red--delawares and 1 w/leghern----don't know if breed is a factor also-----now ,

,..how to do it ???

...any help is appeciated