How do I represent a sharepoint user type in a K2 workflow?

I have a sharepoint list which contains a column of type Person/group. I want to look up an item in the list, and then assign a task to the user who is saved in the this column.

Can anyone tell me how to retrieve the user so that I can use it to assign a task to?

 Sorry if this is very basic - I'm vey new to K2

 Thanks in advance for any assistance.