Making a cheese sauce can be great to use in a variety of different meals.
To start off, make some Bechamel Sauce, the link for that recipe can be found HERE.
Once you have your Bechamel Sauce ready, the rest is very easy to do.
Grate the cheese of your choice - Any cheddar cheese will be fine, but try to avoid using parmesan or mozzarella.
Stir in your grated cheese, around 100g should be fine.
Keep mixing this until all the cheese has melted and you're left with a cheesey smooth mixture