How do you unlock boards on monopoly streets?

There's no such thing as "unlocking boards" in Monopoly. You can't "unlock" properties or streets. In Monopoly, you buy properties and build houses and hotels on them as you play the game. Here's how it works:

Buying Properties:

1. Landing on an unowned property: When you land on a property that hasn't been purchased, you have the option to buy it from the bank at its listed price.

2. Paying rent: If you land on a property that is owned by another player, you must pay rent according to the property's rent rules, which can vary depending on if houses or hotels have been built.

Building Houses and Hotels:

1. Owning a color set: You can only build houses and hotels on properties if you own all the properties of the same color group.

2. Building costs: You can purchase houses from the bank for a specific cost. Once you've built a maximum number of houses on a property, you can purchase a hotel from the bank.

3. Rent increases: The rent for a property increases as you build houses and hotels on it.

There is no "unlocking" involved in the game. You purchase properties as you play, and then you can build houses and hotels to increase your income and your chances of winning the game.