Farming was released in MineScape on August 8, 2019.
This guide is under construction and needs volunteers to help write it.
For now, use the OSRS wiki for the basics of getting started.
The command "/items seed" will list all items in the game with "seed" in the name. You can then hover over each seed to see where it is sold, or what monster drops it.
The command "/mobs mobname" can then show you that mob. Left click it to see the drop rates. In many cases the drop rates are similar to the ones found for the mob on the OSRS wiki.
Mammoths can be a good source of seeds. They are found in the wilderness just north of the GE.
You can buy starting supplies in the store just north of Port Sarim.