Knowmia has a very good captioning option. But Otter is better to use if you need editing tools like find/replace. In videos longer than 5 or so minutes, it would be worth your time to use Otter.
This article assumes that you have already published the video in Knowmia and created the captions in Otter.
Click here to learn how to create captions in Otter
(If necessary, click here to learn about creating videos in Knowmia.)
Open the Captions in Otter by clicking on its name in your list.
At the next screen, click the three dots at the upper right corner for "more options"
Then click the "Export" option.
These settings are important for Knowmia
This sequence will create and download an SRT file that has the same name as your video.
Find it in your computer's "Downloads" folder.