There are different ways of relating to your bass. It is very important to understand theory, and that is one way of relating to it; however another is to relate to it using patterns. Patterns are simple, and lock in perfectly with your theory.
Essentially, learning the patterns will get you going quickly, and then learning the theory will make you more versatile. The I IV V Perfect Harmony Box is a super important and useful one to know on the bass.
One of the most important things you really need to understand, regardless of how you approach the bass, is tones and semitones. Make sure you’re familiar with that lesson before diving into this one.