You need:
As much yogurt as you want, whole yogurt preferably because otherwise you won't have much final product.
About a tea spoon worth of salt for every cup and a half of yogurt.
Mix the two welll.
Pour into cheesecloth, or a clean dishrag will do. Suspend over bowl or sink for 5 to 8 hours or until you have a somewhat firm but still creamy texture, will look like spreadable cream cheese.
Voilà, Now you can eat that with just about anything, fish, vegetables, sandwiches you name it. Nice little recipe: Pita bread, labneh spread in ample quantity and any type of marinated olives, roll up and eat.