I' m by no means a pro but this is how I do em.

purr - I vibrate my lips a little and make the tone come out of through them(people have told me it sounds excellent) I know some people say not to use lips but it works for me.

cluck - put lips together and build up air pressure in mouth then puck like a chicken.

cutt - just kuck into the reed (I think of throwing the air into the top of my mouth not out)

cackle- the hardest for me to learn by far. I learned by practicing just saying cack, cack, cack, cack , cack , ...etc without a diaphram then do it with the call. A thing that helps me with my cackles is to start out with two or three clucks then roll into cackle

hope this helps