How do you link all echo devices together?
To add multiple Echo devices to a single group from the Alexa app, tap Devices on the bottom-right. Select the plus (+) icon on the top-right and select add Multi-Room Music Speakers. Create a custom name for your group or choose one of the common names (Everywhere, Kitchen, Bedroom, etc).
I'm not sure what it is you're wanting to do but to link all the speakers to play music throughout your house perhaps go to your settings and each device and under speaker you'll have the option there otherwise they are pretty much linked together, you can name them individually.