I was playing your game a little bit, in freeplay, and build this factory.
This is the overview of the factory, the resources are coming from top, through filters, furnace lines and to the assembling machines:

These are the filters, split iron, copper and coal to three different belts:

Then everything proceeds to the furnaces:

Finally, everything is used in assembling machines, mostly for research packages and some basic stuff. I still don't produce enough of everything:

Here I produce blue science packages, which are very costly:

And finally, I have one separate small factory just for rockets because I need plenty of them:
