I use Google Slides all the time for my professional development presentations. With the COVID-19 pandemic forcing most of our training opportunities online I have had to hone my presentation skills to meet the demands of virtual presentations.
The first and most widely used method of presenting a Slides presentation is by using the Present button in the top right corner in Google Slides.
If you click Present, the presentation goes full screen and starts your presentation on the slide currently selected in the sidebar. You exit full screen with the ESC key. Now, presenting full screen is great if you are presenting to an audience as it will fill the screen and make it easier for everyone to see.