It is common to use the Gantt chart to see an overview across all of your projects' or team's milestones. There are a few steps you can take to create this focused view and cut out the 'noise' of other, less significant tasks.
First, add a filter of ‘Milestone Type’ using the filters at the top of the page. You can choose to view All Milestones, or just a particular type of milestone.
Then go into Gantt Options, using the ‘three dots’ symbol on the right-hand side of the screen. You probably don't want the rows of Projects and Task Groups, so see Show/Hide Columns and Rows, and click Rows. You can hide those rows there.
If you need to see the Projects and Task Groups for reference, you can then go into Columns, and choose to display the Projects and Task Groups there instead.
Finally, you can use the Timeline Restriction tool, just below, for example if you are only interested in upcoming milestones.
You'll end up with a view like this - perfect for exporting as a PDF or PNG, also available in Gantt Options.