Hover on Settings > Monitoring > Probes > Click on Network nodes and services tab, where you can find Radio button in start of table to bulk select entities. You can also use keyboard shortcuts to select devices After selecting, click on Setting icon ...
To edit an already added configuration Navigate to Settings > General Settings > Integration. Click the tick mark icon next to the channel count in the Slack widget. You'll now see the list of channels that have been added. Select Edit/Delete under ...