Unless you have a very uncommon name to search I don't advise going in to search from the home page. After clicking on any of the categories below try clicking on Browse Record Collection to see the types of records each category contains - they are not always obvious.
Click on Search All Records. Again, I would not search all records unless you have a very unusual name.
Birth Marriage and Death including Parish this category also includes WILLS and Cheshire Wills are fully downloadable.
Census Records Land and Surveys, you can search all categories here, but I have had more success clicking on A-Z of Record Sets and searching individual years. 1911 Census has also restored Address Search. This category also includes Electoral Registers 2002-2013. They have now name indexed the English Electoral Registers 1820-1832
Directories mostly Companies House Information.
Education and Work India Office, Merchant Navy and Schools Admission etc.
Military is self explanatory.
Travel and Migration also self explanatory.
Newspapers and Periodicals World Wide subscription has access to American and Irish newspapers in addition to the British Newspaper Collection.
From the main home page click on search in the top menu bar and then All Record Setshere you can search for any records sets such as passenger lists and go straight to the source I wish to search, for instance type passenger lists in the search box to go straight to their search screen. You may have to be a bit creative here eg MILITARY just produces record sets for Military Nurses, but ARMY will produce the databases you probably want to search. You may also want to see what FMP has indexed for other parts of the world here by clicking on the country of choice.