You can add a button component in the components menu. You can drag the component button to your timeline or to the canvas. You can also press the three dots located to the upper right of the window, after which you would have to click ‘place element’.
The button can easily be moved across the canvas by dragging it with the cursor. You can change the size of the button with the transform tool (see toolbar, located on the left side). By holding shift while enlarging or shrinking, the initial proportions will be preserved. Position the button on the desired location on the timeline to determine the moment it will appear.
Interactions are configured by selecting the desired button and by adding the interactions of your choice in the interactions menu. Click on the round blue button, located in the interactions window, to create a new interaction.