Open Google Slides and create a new presentation
Select a slide layout with enough space for your timeline
Go to Insert
Click Diagram
Choose Timeline
Select a timeline style
Enter your dates, milestones, and labels in the sidebar
Adjust the number of events if needed
Click Insert to add the timeline to the slide
Resize and reposition the timeline
Edit colors, fonts, and shapes to match your design
Add icons, images, or text boxes if needed
Duplicate slides for additional timeline sections
Save or present your timeline when finished