After installation, the App scans the store and get all the translatable text from Shopify, so you can find and translate them in the App. After that, App periodically scans the store to get new and updated text, so you can use the App to keep the translation up to date.
If you cannot find some text in the App, one of the common reason is that the text were added to the store after the previous scan, and the next scan has not started. In this case, you can also manually trigger the scan in the App by going to "Manual Translation" page >> at the top of the page, there is a button named "sync items", click that, the App will start the scan shortly. Please refer to the screenshot below. After that, you should be able to find the text.
If you still could not find the text after the new scan, please email us at firstname.lastname@example.org. We will help out.