Hello,
I am suggesting that there should be info for Farmer job in F1 clivian window, here I came up with some info you can add more below if needed or to fix any mistakes.
You can get this job from at Flint country, The farm, you can use /gps easier.
Once you have got this job buy some seeds from the yellow marker that is next to it then go to the yellow squares that are available in your minimap and go to the blue markers and spawn a "tractor" to plant your seeds, you can use the by just driving over the yellow squares that is in your map, once you have done planting your seeds use /djv and wait till it grows and become bigger and it will be marked as a very small green blips in you minimap /map, when it become bigger go to the blue marker again and spawn "Combien Harvester" and then drive with it over your plants and it will get auto transferred to a bale after you finish harvesting use /djv again and walk over those bales so you can get your payment.