you can explore or attack
since you are probably new, you want to explore
first, buy some scouts by going to "build ships"
dont build too many, keep in mind the money you have
and then explore, be careful though, whatch your power rating 5k protection ends at 5,000 power, after thyat you are open to attack
but after exploring, be sure to disband your fleet, because, all ships require a maintenance fee per turn called "upkeep" so, if you kept your ships, it would slowly (or qickly) eat away from your funds and drive you into debt. so that is something to be careful about
be sure to read tha manual as well, it helps cover most of the basics and then some