You'll talk to other factions, trade for goods and technology, and then use those goods to build improvements and structures on your owned planets. Eventually, you'll open that to free movement and teleporting with new options like Warp Drive and Hawking Radiation Dowser, which come from specific research opportunities in the extensive tech tree. You have your exploration, which begins constrained, with your ships only able to travel across space lanes that connect star systems together. The core of the game carries forward from the previous entry and the 4X genre in general. Can they do the same in a more crowded space? Spoiler alert: The space is not actually endless.
In 2012, the studio surprised with an excellent entry into the genre. Into this cluster comes Endless Space 2, the sequel for Amplitude Studios' debut game. There's Galactic Civilizations III, Stellaris, Master of Orion, and Distant Worlds. After some cold years, the 4X space genre is pretty well stocked right now.