There's a thread on here about will the Acoustimass 300 to Work with a 700 Soundbar and the conclusion was that it will. I have just got this combination and so far I'm unable to connect the 2 together. I'm trying through the Bose Music app which can't find the AM300, is that the correct way or is there something else?
I'm not sure how to connect it wirelessly but you could use a wired connection. Are you on the correct frequency of your router, either 2.4 or 5.0?
Isn't there a light on the back of it? I don't remember.
When you set up your Bose Soundbar 700, I think you had to attach it to either 2.4 or 5.0 if you have a dual frequency router, which you probably do. Whatever device or cell phone you are using needs to be connected to the same router frequency for you to be able to run the Bose Music app needed to connect your Bose Acoustimass 300.
Maybe if you unplug the Bose Acoustimass 300 and wait a couple minutes, then plug it back in. Maybe it will then show up in the app. You could try that with your sound bar also. You could even reboot your router and cell phone. Many times, rebooting stuff solves a lot of problems.