Love stone - through sex (and also through drilling pink heart tiles in drilling minigame if you have Cami in your squad). Workers (looks like white human) can be born through impregnation or bought with love stones, 25 love stones for 1 robot (cheaper during discount event).
Each other resource is tied to a specific type of biome. When you walk in a tile of this biome, you get one unit of this resource. When you're drilling, you can drill a colored tile to get more of this resource. You can place a drill on any tile to gain one unit of this resource every time you move on the map (probably bug). When you drill a big golden tile at the end, you install a flag, that allows you to move to this space with half energy cost (therefore, it will double harvesting from drills and villages, once again this is probably bug). If one tile have a drill and a flag at the same time, you can place a village there to double your resource income from this tile. If you turn a room (with or without a girl, probably bug) into a milking room (impossible for your own room), then you will get +1 energy, so you can move more times. Right now there are 7 rooms available, so it's possible to gain 14 resource units for each drill and 28 resource units for each village you placed.