OK. So where is the link to enter the 1950 census indexing?
There are several ways to get there. Probably the most straight forward is from the "Get Involved" drop down menu that is at the top of Family Search pages. Click 'Get Involved" and then click "1950 U.S. Census". The link is shown below.
Please note that the "Indexing" for the 1950 census is actually reviewing what the computer has already indexed - the computer makes the first pass at indexing and then we review and correct. So it is different from other indexing projects where people perform the first pass indexing.