How is the search for the item supposed to find the specific item if the data is all clumped together and all the search is given is the output of the hash function. I don't understand how it knows which of the pieces of data is the one that corresponds to the key if linear probing has been used so it could be any of a number of pieces of data? Thanks for any help
Any given equality function over the objects. You're asking if an object is in a hash table, and it is if there is an object that is "equal" to the given object.
And remember that object equality implies hash equality.
In linear probing, The hash function only points to the bucket in the hash table that is the starting index for the search. So say item $x$ after hashing has a hash value of $h(x)$. This is just the starting index of the bucket. If the data at hash bucket $h(x)$ is not equal to the data, we incrementally search $h(x)+1, h(x)+2,....$ till either the data is found or an empty slot if found.