Adding to a group
Add ChatZilla to a Telegram group from the mini app, the start button or the group itself, and see what happens after you add it.
From the mini app (recommended)
Open @ChatzillaBot, press Manage chats and then Add chat. Telegram's own picker opens with the required admin rights already selected: choose the group, confirm, and the bot is added and promoted in one step.
With the Add to group button
The Add to group button under the bot's /start message opens Telegram's group picker as well. After adding the bot this way, check that it is an administrator with the rights listed in Permissions.
From the group itself
Open the group, choose Add member, find @ChatzillaBot, add it and promote it to administrator with the rights from Permissions.
After adding it
The group appears in the mini app under Manage chats; open it there to set the rules. Until you change anything the bot lets all content through: filters, verification and anti-spam all start switched off.
To stop the bot, remove it from the group's members. Unlink chat at the bottom of the group's screen in the mini app turns its settings off but leaves the bot in the group; to bring it back after that, remove it and add it again.
Forum groups (groups split into topics) work the same way. All topics are moderated, and the language filter and triggers can also be set for a single topic.