You can add a pause or delay in your script by adding (pause:Xs) in brackets and mentioning the number of seconds you want the voiceover to be delayed.
From the Edit script section:
As shown in the screenshot, you can manually add the (pause) between chapters from the edit script section.
You can remove the pause from the video via the Magic box:
Remove all (pause) from the video.
Or if you have a pause with the duration mentioned, you can use this command:
Remove (pause:3s) from all chapters.
You can add a pause in between lines/chapters if you want only the Media with the music to be playing.
You can add new lines between sentences as shown here.
Note: You have the option to change the speed of the voiceover now as shown here.