I think I have a vague understanding of what these terms are actually referring to, but I was wondering if anyone could help me with a concise explanation, and what differentiates tactics from strategy? that would be great!

Tactics are the short-term operations you perform on the board, like forks, skewers pins etc. Strategy is your long-term plan.

Positional play refers to making moves to fullfill your strategy (but can offcourse have tactical "side-effects").

"Amongst masters, combinative and positional play complement each other. With combinations, they attempt to refute false values, and by positional play to demonstrate true values." Emmanuel Lasker(1868-1941), world champion for the longest period ever: 1894-1921

While this  may not be so much help by way of a definition, it is a wonderfully destilled phrase about the nature of chess