This is a story mission that cannot be missed. Basically, in one mission you will get a device to create a portal home. Next story mission will try to start it. It will fail due to lack of energy. (Later forcing you to protect it for digging singularities). During the attempt to open the portal, your base will be attacked a few waves.
*Note, if you fail you will be reverted to the last save our base will be restored.
I found the easiest way to build a few layers of normal walls (Chain-link) and use a spear to stab through it. Molotov's proved helpful as well.