I'm fairly new to this software and I'm currently working on some drawings for practice. The picture below, I'm a bit at lost at how to cut the 12 channels of 55 degrees helical slot. I've looked through older models drawn but I am unble to get the same results. I've tried reaching out to the people who did the modeling however uncontactable. I really need help with this. Thank you and waiting for your response!
I would draw a sketch of one 30degree (i.e. 12 cuts per revolution) arc section of Section A-A and another sketch line down the axis of the part. You can then use the helical cut to sweep that cut around the part - the trick is to go into the options for the helical cut and choose perpendicular rather than parallel which will work better in this case. Obvoiusly you can change the pitch/turns etc to suit.
In your model it appears that there's two different cuts that are alternatly patterend around the circumfrence so I'd do the two slightly different 30degree (around the circle) cuts, then pattern the two features 6 times around the shaft.