 So now we have the notes root, fifth, octave, and dominant seventh to play our walking bass line. Let's add a couple of chromatic transitions to get us smoothly to the next chord change. So I'll show you what I would do if I were doing something like this. For the B-flat chord, I have it for four measures. So one, two, three, four. Now E-flat, B-flat, F, B-flat, F, B-flat. So I'm keeping that frame where I want it. My first finger is firmly anchored on the root. And from there I know that this is root, this is fifth, this is octave, and this is seventh. And then I can use a little chromatic transition to get from one chord change to the next. Give it a try, try lots and lots of different patterns. The more you do it, the more you'll develop a vocabulary of patterns that you know you can use over each chord change. And you'll get better and better at it with more practice. Give it a try and good luck.