1
Tap Settings at the bottom and select Subtitle.
2
You can set Full Styling and Embedded Fonts in SSA/ASS.
3
Open an SSA/ASS subtitle file.

Activated Full Styling and Embedded Fonts

Activated Full Styling and deactivated Embedded Fonts

If you deactivate Full Styling, graphic subtitle appears like a text subtitle.
Text subtitles can be repositioned and resized.