Unfortunately, wireless signals are not "just out there" to be enjoyed by all, gratis.
Even in your hotel, someone was footing the bill for the internet access that you enjoyed during your stay there. The cost was factored into your bill.
At the top of the screen, no matter what application you are running, you will find the Menu Bar. It is anchored by the Apple menu at the left hand end and the Spotlight icon at the right end.
With no applications running, you will see, left to right, the Apple menu, Finder, File, Edit, View, Go, Window & Help
At the right hand end you will see a magnifying glass, your name, and a few other things.
Open System preferences, it's in the dock, and go to Network.
Click on Wi-Fi in the left hand column
In the right hand column, click in the box next to "Show Wi-Fi Status in the Menu Bar"
Now on the left side of the screen, in the menu bar, you will see a Fan shaped icon. Click it and you will see things relating to Wi-Fi and a list of all the Wi-Fi networks that your Macbook can see.
Any that do not have a padlock on them, are open. OK for surfing but offer no protection at all.
Ones with padlocks require a password to join them.
More about wireless in the next post