SoundCloud is the world's leading social sound platform where anyone can create sounds and share them everywhere, including directly from your Cindr site.
To add a SoundCloud Bloc go to the site editor and from the side menu select 'Add Blocks' > 'Apps', scroll down until you see the SoundCloud logo and click any of the available Blocs.
To change the audio first open another tab in your browser and go to SoundCloud. Find the audio that you want to add to Cindr and go to its main page. Under the main image you should see something similar to this:
Click the "Share" link, then the "Embed" tab.
Copy all the text in the input (starting with <iframe), then go back to your Cindr site, click the Bloc to active the 'edit mode' and hover your mouse over the existing audio. Click to go into the Bloc settings and paste what you copied from the embed. Click the "X" to the top right and the clip should be updated.
Remember to save/publish your site to reflect any changes you make.