for short ,when you create a table you need to select the partition scheme and file groups.In partiton scheme you will mention partition function .

Now the clustered index has the data as well so it will automatically be partitioned as per the partitons you mentioned for the table.

for non-clustered index you can again mention the filegroup and the partiton scheme .

this way you will reduce the IOs as the complete data will not be accessed but only the partition where that data you are requesting resides.

Regards