If his father (parent) already has a WikiTree ID - enter the data on your ancestor
and then choose [add parent]
enter his father (parent) you should get a message that lists possible matches with this parent.
There will be a list of any William Durkee's already entered - you can click on any of those listed profiles to look for matches -
If you find a correct match - on the left click on that radio button/circle - then at the bottom right of the list - click the bar at the bottom that says:
Selected Person is the Same William Durkee