Basics

Consider setting up a broadcast channel only if there’s a strong need for it. Does your team have the capacity to moderate the space and a process in place to generate content for the channel?
Be aware of the channel’s place in the wider movement and the issue of comms burnout. Less is more.
A system is needed for people to send messages to broadcast. This can be via a dedicated email address, DM-ing the Broadcast coordinator etc. The system needs to be communicated to your group so it’s clear how to use it.
Manage expectations by giving criteria for what will get broadcast.
Assign a Broadcast Coordinator to process messages.
Encourage your group to follow the Rebellion Broadcast and the Movement Broadcast (for key XR UK info) to help reduce communication overwhelm.
If you are using Telegram, consider syncing it to Mattermost via a bridge to serve both platforms.

In local groups, this process may be simpler as the broadcast may be help by an individual.

Establish a closed chat for the broadcast editors team.
A new message request is sent to the broadcast team, following the system chosen by your group.
The post is shared into the broadcast editors team chat with date/time request.
The broadcast coordinator schedules the post.
The broadcast group gives feedback or edits the post, checking details for accuracy, clarity, inclusive language and formatting.
Once agreed, the final post is broadcast and others can draw on the content knowing it’s accurate.

Limit the number of messages and have a balance of content. Stagger them over a period of time in the run up to an event (if appropriate)
Have a broadcast communication plan and build up to events as part of a wider strategy.
Leave time for your message to land (usually 2 weeks, 1 week minimum to promote an event). Last minute calls to action can be counterproductive and induce stress.
Don’t share messages elsewhere before they’ve gone out on the main broadcast. It can be confusing for people to receive different versions of the same info and reduces the likelihood of mistakes being shared.
Top tip: you can share the LINK to a Telegram message, rather than the whole message. Right-click on the post in the broadcast channel and 'Copy Link', then post this link in your chat. This saves space and steers folks back to the main broadcast channels - if you want to flag a post there.