To use Mote in Google Slides you first have to install the Chrome extension. Once you've installed the Chrome extension you'll then see a Mote icon near the "Present" button in your Google Slides editor. Click that icon to start recording. The free version of Mote lets you record for thirty seconds. After you stop recording you can then play it back. If you like your recording, just click the insert button on the Mote menu to have it added to your slide. If you don't like your recording, just hit the trash icon and try again.
The first time that you use Mote you will have to grant it access to your Google account. That access will include accessing your Google Drive. That access is necessary because the way that Google Slides handles audio is by playing it back from audio files that are stored in your Google Drive. It's for that reason that you'll find your Mote audio recordings are stored in your Google Drive account.
Just like inserting any other audio in Google Slides, Mote audio recordings can be set to playback automatically when you are presenting. You can also set the recording to play on a loop. More details about adjust audio playback in Google Slides is available here.
Applications for Education
Mote could make it a lot easier for teachers and students to add explanatory audio to Google Slides. Just remember that if you're going to share your slides with students, you'll need to change the access settings for the audio file in Google Drive to "anyone with the link can access" otherwise they won't be able to hear your audio file. I explain and demonstrate that setting in the last portion of the video (about the 3:10 mark) that is embedded above.