https://www.pcgamer.com/fallout-76-trailer-shows-off-camp-basebuilding/

The Garden of Eden Creation Kit—the G.E.C.K.—is a device of singular importance in the Fallout universe. It's a portable terraforming technology that can transform blasted chunks of wasteland into viable, life-supporting land in very short spans of time. In Fallout 76, players will establish their post-war settlements with a similar, but still very different, device called the Construction and Assembly Mobile Platform—the C.A.M.P.

The Camp (which, like Stalker, is how we will be stylizing it) is more of an emergency quick-start device than the Geck, providing "shelter, supplies, and safety" rather than a wholly-changed environment. It will also enable players to set up trading outposts to exchange goods with other players—the ones who aren't inclined to just take what you've got by force, anyway. The settlements look more primitive than some of the big, sprawling bases that were built in Fallout 4, although whether that's by design—Fallout 76 is set nearly 200 years before Fallout 4, in a wilder wasteland—or simply because nobody's had time to do anything really crazy with it yet, isn't clear.