Earth was once like that
Do recall that every atom on Earth originate either from the Big Bang (Hydrogen, some Helium) or the fiery fusion furnace that is the center of a star, which then got thrown out into the universe from the massive force of a super nova (everything else).
This was then collected into a swirling ball of hot gas, which then became a molten ball of lava, which - for the most part - it still is, it just so happens the surface has cooled enough so that life as we know it have formed and started using the stuff that was on it.
This means that life is not necessary to create all the things that you need. Life has for instance not created the Calcium that you find in limestone deposits, it was already there. Life just accumulated it for you.
You can synthesize "everything", with enough energy
I put "everything" in quotes because there are some complex substances that we humans have not yet perfected creating. But for all the simple stuff, like Calcium Carbonate and Calcium Silicates that you need for making cement, you can synthesize, as long as you just have an abundance of energy.
So you bring your reactor, either plain old fission reactor running on Uranium or Thorium or discarded Plutonium, or a handy little fusion ditto like a Polywell running on Boron and Hydrogen. These are the first thing you then mine: fuel for your reactor.
Next up you want to sustain yourself. For that you need water, air and fertilizer. Using the energy from your handy reactor you reduce minerals to extract Oxygen, Nitrogen, Hydrogen, Phosphorous and Carbon Dioxide. From this you start your hydroponics. Then, using the plant matter from these, and the load of useful soil bacteria you brought along, you can start making real soil.
In the mean time you are also busy extracting all sorts of primary materials, Silicates, Calcium, Iron, Aluminium and so on, to be used for construction materials.
I am not saying this will be easy or efficient, but if you just hand-wave away the difficulties in producing energy — by for instance assuming that fusion is viable and works as well as we hope it will — then you will have all the starting material you need to get going.