On the front of what? 

From your question, the only possible answer is “to touch”.

I think the forum auto-tags each new post based on what products the poster owns, so the only assumption that seems valid is that the question refers to an Amp.

It’s rather surprising to find that the Sonos documentation on the Amp says almost nothing about the touch controls.

Are you asking because they do nothing when you touch them? My understanding is that, like any other Sonos product with touch controls, they can be enabled and disabled in the app System setting for the product. Have you checked to confirm that the controls are enabled?

I am afraid to touch them. The amp works well enough but the instructions are very vague.

Vague?? IMO they are quite clear and there’s nothing to be afraid of. See below:

Here’s the link to the Amp user guide:

https://www.sonos.com/en-us/guides/amp

Thank you.

Nothing like that came in the documentation with my AMP. Maybe it got left out somehow.

I did not know what they were for so I did not try them.

I know now thanks to AjkTrek1