You have 3 options to anchor your subtitles within a text box: Top, Center, and Bottom.

By default, the anchor point for a text box is set to the center.

For example, if you choose Top, any new text added to the box will appear below the existing text. The top of the text box will remain fixed in its original position, and the box will expand downward to accommodate the additional text.

On the contrary, the newly added subtitles will appear above the existing text.