To select one or more series, use a pointing device (mouse)  combined by CTRL-key. In the abscence of a pointing device, use Tab-key to navigate through, browse/select items with up/down arrow keys and Enter-key to choose an item menu or a button to submit your selection. 
On the series listbox, type the first letter to jump to a particular serie(s). For example (L) for Labour force.

The .pdf tables cannot be accessed from the 'Data Selection by Series' screen. To access them, please click the relevant link on the left hand side menu.