Create a new composition in AE. Select "file"->; "new"->; "Composition", and set the composition size, duration, frame rate and background color as needed.
Create a text layer in AE. Select "layer"->; "new"->; Text, and then drag the icon of the text layer to the timeline in the composition panel. The text editor window will pop up.
Enter subtitle text in a text editor. Enter the subtitle text to be added in the text editor, and then adjust the text properties such as font, font size, color and alignment in the text editor window. After editing, click OK to save the changes.
Adjust the position and duration of the text layer. Select the text layer in the Timeline, and then drag the text layer to the desired position in the composite preview window. You can use the endpoint controls in the Timeline to adjust the duration of the text layer.
Optional step: Add styles and animation effects. You can add various styles and animation effects to AE to make subtitles more vivid and attractive. By applying AE's built-in effects and plug-ins, or customizing production effects and animations, various visual effects can be achieved.
Render the output subtitles. Render and output your work in AE to generate a video file with subtitles. Select "synthesis"->; Add to Render Queue, then set the output format and other rendering options in the Render Queue window, and finally click Render to output the subtitle video.
These are the basic steps to add subtitles to AE. You can make further customization and adjustment as needed to achieve more effects and functions.