Complex projects have many milestones which can overlap with neighboring milestones when placed on a timeline. With Diamond or Triangle milestones markers, the text for each milestone can overlap each other as shown below. Re-positioning your milestones can help with spacing, allowing you to fit more milestones onto your slide, without having to abbreviate the text description for each.
With Office Timeline Plus edition you can manually position the text and date box of each milestone, and create a connector to it. This can be done for milestones that are positioned above or below the time band. To do this click on the text box of the milestone you want to re-position and drag it vertically up or down to the new position. Once in the desired new position, click the Accept button on the tool bar which will create a connector to your newly positioned milestone.