My son(5 years old)and I would love to start a home container tomato and cucumber garden.?

BUT we have No clue how to get it going?????
please answer if you really know how to get a container garden going from the very basics. Thank you for your time.
Also, we would like to use all organic materials.

good on you both, use a bag of potting mix , slit the middle and plant what ever plants you have,use stakes if you have to , min 6 hrs sun is needed, when finished you can use the mix by putting into pots for growing flowers, have fun , tou will learn from the experience.