Quick ways to create and join channels through actions menu in LHS
Apart from the main '+Create/Join', channels can be created under each level separately through actions in left sidebar. These actions are provided to create and join channels instantly.
To do so, click on Actions icon straight to each channel level heading and select Create. The create channel dialog for that level will open. You can also choose Join under Actions. This will open a dialog with the list of all channels you can join in that particular level.