The Explore, Discover, Build, and Conquer buttons on the Base Control Screen activate the Governor for that base. When the Governor is activated, he will make decisions automatically based on his general instructions. This function is useful for beginners and for players who do not wish to micromanage their bases.
The EXPLORE button tells the Governor of a base to concentrate on finding and occupying new territory. Bases set to explore will typically concentrate on building Scouts, Colony Pods, Transports, and occasional Naval Units for scouting oceans. This button is especially useful early in the game, when you need to expand quickly.