How to Edit a Paint Action Sequence
How to Combine Paint Action Sequences (PASeq)
Another article you might find useful is how to combine steps from different Paint Action Sequences to make a new PAseq using the History Sequence
How to Edit Text in a PASeq Step
Regarding the the text. Click on the red square next to the step that has the text. This should bring up the Paint Synthesizer, toggle to the editor which is at the bottom of the preset window. (if it is not you can open the editor Windows > Editor
Once you are in the Paint Synthesizer editor toggle to Brush Source. This is where you can change the text.
Once you change your text you need to update the Step in the Paint Action Sequence by Option Clicking (mac) or Alt Clicking (win) the red square next to the step you just edited.
Next you need to save your new edited PASeq to your Favorites folder. You can do that by File > Export > Export Paint Action Sequence Preset and then going to the Studio Artist Folder and inside there is a folder called Preset and within that folder is a folder called Favorite. You can create a folder there and save your preset.
How To Mange Your Edited Paint Action Sequence Presets
Here is video that explains everything you need to know about Presets.