Gochujang is one of the core condiments in Korean cooking made by fermented chilli paste. It is traditionally made with sun-dried chilli, brown rice, Meju fermented soybeans, Yeotgireum and salt. It has rich natural sweet flavours coming from rice with a spicy punch from the sun-dried chilli. 
 
It is not overly spicy, it has a more balanced taste of spicy, salty, sweet and savoury. Try this on your stew, stir fry dishes or simply with a bit of rice. 
 
Here is some good recipes by Bon Appetit 
https://www.bonappetit.com/recipes/slideshow/gochujang-recipes