There are no bass notes in the chords below, but even without the roots you can still hear the shifting harmonies, particularly if you play the 3 and the 7 of each chord as shown. (For example, in bar 1 I play A# and D#, the 7 and the 3 of Bmaj7, followed by C and F#, the 7 and the 3 of D7.) This provides more than enough harmony for most soloists. If you’re playing in a duo situation, though, you should play bigger voicings, perhaps adding the root of each chord on the fifth or sixth strings. The challenge with “Giant Steps” is that unlike “Autumn Leaves” or other standards, the progression doesn’t allow you to hang out in any one key for more than a few beats. This is one tune that requires you really make every change.
Rhythm is the other important element of comping, and that’s hard to teach on paper. What’s shown here is just an exercise to get you going, which means it’s far too literal in its phrasing. There are an infinite number of ways to phrase these little chord stabs, and that’s’ where listening comes in—listening is how you learn music. Theory is great, but not on its own. If you don’t combine theory with true listening, then, well, fagettaboutit.