For each service, this is the list of items found in each column:
Service name;
Current Status: either running or stopped;
: click on that button to get a little explanatory text on that service;
On Boot: check this box if you wish this service to be automatically brought up at boot time;[1]
: immediately starts the service, or restarts it (stop+start) if it is already running;
: immediately stops the service.
[1] | Generally in runlevels 3 and 5 |