There are multiple city transportation options, including the elevated trains(The "L") and buses. You can map out public transit directions by looking it up on Google Maps, Apple Maps, or any mapping option on your phone. To buy tickets, you can go to a train entrance and purchase physical tickets, or you can download the "Ventra" app and purchase virtual tickets on your phone. City tranit is a cheap and easy option for moving between neighborhoods from downtown up to Wrigleyville.
Uber and Lyft are easy options to find around the city. Downloading the apps on your phone and using them should be a reliable choice.
Use those legs!