I don't understand what you need. In one post you say you want to display dates but in your latest post you say you don't want dates.

The Bar Styles dialog box is where the bars are defined for each type (task, manually scheduled tasks, summary tasks, etc.)

If you want to draw a bar for tasks - there are already bars for "Tasks" and lower in the list Manually Scheduled. For both, the bar is drawn from "Task Start" and Task Finish"