The current mode is shown in yellow on the Modes Toolbar in the top right of the screen. Simply click on the desired button to select a mode.
You will normally work in Edit Mode when creating and editing subtitles. A more limited set of editing features is supported in the other modes.
Fix Mode can be used to capture timecodes manually whilst the video is playing.
You can use Replay Mode to replay the file against the video in order to check the subtitle timings.
In Q-Live, additional modes are available:
Click here to learn more about how the different modes operate in Q-Live.