I believe that each participating country just uses their own standing armies to come together for any NATO operations. There are NATO designated generals/admirals and stuff though, so these generals from different countries within NATO then lead and direct the combined troops. There's a Supreme Allied Commander Europe for "army"supreme and Supreme Allied Commander Atlantic for "navy" operations.
Since there is no exact collective standing army, signatory nations are expect to spend at least around 2% of their national GDP on their national military. That way, if NATO actions are needed, there's enough people and equipment to do the operations, without having to have separate NATO troops. How they determined to use a level of 2% GDP spending, I don't know.
I believe that each participating country just uses their own standing armies to come together for any NATO operations. There are NATO designated generals/admirals and stuff though, so these generals from different countries within NATO then lead and direct the combined troops. There's a Supreme Allied Commander Europe for "army"supreme and Supreme Allied Commander Atlantic for "navy" operations.
Since there is no exact collective standing army, signatory nations are expect to spend at least around 2% of their national GDP on their national military. That way, if NATO actions are needed, there's enough people and equipment to do the operations, without having to have separate NATO troops. How they determined to use a level of 2% GDP spending, I don't know.