The Factory Must Grow - [Book 1: The System Must Live] (You may have me outnumbered, but you are clearly outmatched!)

Most of the professional isekai-ers known as Forerunners arrive on worlds in the midst of crisis. Be they invading armies, impending calamities, or unstoppable monsters, the Forerunner Program prepares and sends out teams of five to intervene in apocalypses across the cosmos, then to rally the full force of their saved worlds to create a portal home. The Forerunners do not prepare to land in endless uninhabited wilderness with no gear and with broken Systems. But if Oliver, Alyssa, Henrietta, Clark, and Jacob ever want to get home, those are exactly the conditions they'll have to tend with. And when faced with a problem that requires the manpower of an entire civilization and only five people to work it, only one option presents itself: The Factory Must Grow. [Additional tags: base/factory-builder survival crafting]