You can add a ready-made slider gallery or create one in the block you are working in.
To add a slider, choose a place where you'd like to add the block and click on the "Plus" icon:
A list of the blocks will appear. Choose a slider block which suits you best. These blocks can be found by the controls to navigate the slides:
In certain blocks your can create a slider off the items that you added as a collection. For that, enter the collection settings:
Navigate to the Slider tab:
Enable the slider mode:
Now you can choose the type of the controls and their color:
Check out the article below to learn how you can set the slides to autoscroll: