After loading the media and subtitles:

• Click the subtitle text or time stamps to edit.
• When editing a subtitle text, press shift + enter to split the subtitle into two.
• Click the icons to add, merge or delete subtitles.
• Drag the dashed borders on the waveform to change the subtitles' time stamps.
• Remember to click "Save SRT" to save the subtitles after you finish editing!