Slack – How to Add Same Sidebar Section Groupings for All Users

Open a direct message and STAR it to keep it showing on the sidebar. This is very useful because it does remove any duplicates that would show up in the direct messages part of the sidebar, so you still have plenty of space.

Set default channels for new members from the official help:

• Click your team name to open the Team Menu.
• Select Team settings.
• Click expand under the Default Channels section.

But you might still not able to change it:

• Note: Note that all team members belong to #general and it cannot be removed from the list of default channels.

While it's not supported to rename the channel and move messages there is an import and export feature.

A possible work around would be to restore the original #general name and export the history of that channel. After that you create a new channel with the project name and import the history form #general into that new channel. This way you would have the project oriented messages in the project channel. What's left to do is to clean up the old messages in #general. You can delete old messages using the archives (FAQ: Edit or delete messages ).