Can someone please explain libertarian philosophy in simple terms to me. I want to understand more about it
In short it means to be fiscally (economics) conservative while being socially liberal, and American libertarianism itself was founded on classic liberalism. A mixture of both political sides in other words, some libertarians may lean more to the right while others would lean more to the left. It is maximum individual liberty for all members in society, and you are free to live your life as you see fit provided you do not impede upon the life of another.
There isn't a single unified libertarian philosophy, any more than all atheists share the same beliefs or unbeliefs.
The only core belief common to all is that government is overbearing and interferes with personal liberty; which, of course, is true to an extent. That's what government is for.
But, in the absence of government, right libertarians believe that people would choose to compete more often than cooperate; left libertarians believe people would choose to cooperate more often than compete. Both have a rather Utopian faith that, without government oversight, everyone would be just hunky-dory.
I'm a libertarian to the extent that I believe that government governs best, which governs least. I'm realist enough to know that some level of government is needed to coerce people to work together, where otherwise they wouldn't (public works, taxation, health and safety regulations, etc.). The rub is that every law or regulation will be found to have loopholes; every time a loophole is plugged, a new one will appear. Thus, it's better to leave most things unregulated.