ore is mined from your colonies (given that they have some)
simply build 1 or more mining infrastuctures, and then spend some turns, and it will mine the ore on the planet
labor=population
so if you need more labor build more housing, each infrastructure requires 1 labor, so to maximize efficency, build just enough housing to populate each land, that way all infrastructure will have labor, and will occupy the entire planet
also, the manual is a useful guide, and answers those questions and a hell of a lot more,so please read that