(mod edit - no need to tag users who have replied to your topic)
When I tried to use the clock component of app inventor, I use that blocks that appears in a video, and my app crash in the emulation (when I connected my mobile to the computer) and it crash when I tried to used the apk
Then, I used the extension. These blocks are the blocks I use for my project (ignore the animate component, because it's another extension and work well, EXCEPT FOR THE DELAY FUNCTION (I can't with that ))
The link of the extension is that: GitHub - fvarrui/AppInventor-Extensions: Extensiones para App Inventor