cpstart and cpstop will start/stop all the Checkpoint applications on the box. If you just want to control the firewall components use fwstart and fwstop instead.
To tell whether it is running, do a grep to see the processes (e.g. the enforcement module itself is called fwd) or try the cpstat command
To set up routing you need to do two things. First, make sure that the underlying Solaris system can see the relevant host(s) and networks by adding interfaces and routing table entries in the normal way. There's no point in messing about in the firewall until you have connectivity at the OS level (tried it, regretted it). Once that's all working you can go into the firewall GUI. Set up your new interfaces, then the nodes or groups you want to provide connectivity for, then finally the rules to give you the connectivity you want.
You can get the full checkpoint documentation from