You can add another two column Grid Block to where your Author name should be, and then add the Author name to the left, and a GB Button to the right column. Add a Twitter Social Icon to the button as shown here: https://docs.generateblocks.com/article/buttons-overview/#icon
If however you find the spacing not as smooth as you want it to be, you can place the “by” Headline Block and the Buttons Block in one Container as such, then, we can align it through code: https://share.getcloudapp.com/2Nu7mx8Y