Hello Adrienne, I had this trouble too.

On Ancestry,
bring up the 1851 Census - Isle of Man

on the right hand side of the webpage it says,

Browse this collection
To browse this image set, select from the options below.
Civil Parish
Sub-registration District
Enumeration District

select the Parish you need - and search the pages until you find - Cornelly, Greeba.

this worked for me - I couldn't find my John Fell in 1871 Census on Ancestry - Brian Lawson had given me the information.
by searching the Lonan Parish for Baldooin - I found the image with him on it.

Averil