Thanks for your feedback! You are absolutely right. We actually had the player starting with seeds but somehow stopped working at some point. I'll add a mini tutorial if you'd like to try again!
To start, you can harvest the plant outside (Face it and press Q). You will get some fruits and seeds. Equip the seeds (Q when selecting the seeds) and plant them on the plowed field. Wait or sleep inside the pass the days and let the plants grow. You can sell the fruits in the store and buy more seeds or tools. If you get a hoe, you can equip it and plow more fields!