Open Question: how can i learn to fight?

im more of a lover than a fighter. when it comes to conflict, i generally try to avoid it. or if im angry just turn and walk away, not giving that person any more of my time.
but i realized there are times i cant walk away. as a would be detective, i cant just leave some innocent person to be attacked by someone else.

iv never really been in any fights before (like school or anything). the closest iv been to a fight is some guy pushed a frie4nd of mine. i charged at him and tackled him. we got up and he kicked between my legs….and this wwas in 4th grade e3e;…
im a farly larger person in stature (i guess more of a “tank” character. not “behemoth” or “goliath” really).

what i want to know, is how to effectivly throw a punch, and take one too.
im sorry for spelling errors. kinda tired, and rushed it a bit ^^;
im sorry for spelling errors. kinda tired, and rushed it a bit ^^;