First we get there, comfortably (really?), at Atlantic shipping rates (come on!), and safely (better be!), using the gossamer wings of a JP Aerospace orbital airship, a giant Ascender craft that takes 3 days to attain orbit.
Then, we grab a ferrycraft to transfer us to higher orbit, where the spinship lives. Inside this rotating station is the refinery and farm that transforms space ore into soil, water, and air. What’s left over is metal used to fabricate new asteroid miners and ore barges. That’s what we do in space.
Later, as space industry matures, we make products used on earth. That’s part of saving the earth. The other part is controlling incoming objects from deep space in order to avoid their collision with our mother, dear earth.