This is a simple and basic version of Korean kimchi that can be adjusted to your tastes, i.e. more or less spicy, garlic, different vegetables, etc.
Cut the cabbage into fine strips and put into a pot.
Fill the pot with water and add a lot of salt, until the water tastes really salty. Set aside for 10 minutes. This procedure helps to preserve the cabbage.
Cut the carrots into julienne strips. Cut scallion into rings. Chop the garlic. Put everything into a large bowl.
Mix the vegetables with a generous amount of soy sauce and chili powder until a thick paste is formed. It is advisable to use mild or medium chili powder. You could also add store-bought Korean chili paste to get more complex flavors.
Finally, drain and rinse the cabbage and put it into the bowl with the chili paste. Use your hands to thoroughly knead it and make sure it becomes soft and covered in paste.
Put the kimchi into an airtight container, and let it rest at room temperature for about 2 days, or until it tastes slightly acidic, which means that the fermentation process has begun.
Fermented kimchi will last for several weeks in the fridge.

1 head napa cabbage
Soy sauce
Chili powder
2 large carrots
1 bunch scallion
5 cloves garlic
Salt