Select the Type tool to begin editing your typography.
Click on the layer you wish to edit in the Layers palette.
Highlight the text to be edited.
You can now edit the text, font (Window > Character), sizing and color as desired.
Press the ESC key when done editing.
To resize background boxes to fit your edited text, select the appropriate layer, hit Command/CTRL + T and drag the anchors as needed.
When editing text in the round submarks, you can adjust the text size and letter spacing as needed until your content fits nicely within the circle.