If you're like me and weren't alive to play this game in its' era, an era of playground rumors and limited internet, I think there are 2 correct ways to play this game and trying otherwise is a waste of time. The first way is to just boot it up and explore with no real intention of finishing the game. You'll likely beat at least the first dungeon, maybe you're aware of one random secret from an old game review or an older family member, but ideally you're just using Zelda 1 to chill with a friend and have a fun conversation about the early days of such an important series.

The second correct way is to follow the masterful ZeldaDungeon guide word for word. Zelda 1's secrets weren't meant to be figured out by a single person playing with no outside material, at least not in amount of time that isn't exhausting. So when you essentially remove that aspect of the game with a guide, you'll have more fun adventuring than you might expect, especially since you probably just want to beat it to say you have.