1. In Client Config, on the Business: Cart tab, set Enable Custom Tax Calculation Systems to Yes for the kitchen (it is a per-kitchen switch). Until then the TTR Tax card is hidden and its window shows Custom tax calculation systems are currently disabled.
2. Go to Marketing > Integrations and open TTR Tax (Tax category).
3. For each kitchen section, click the Colorado TTR states field and tick the states where this kitchen should use TTR, then confirm. The selection is saved immediately.
4. Click the TTR API Key field and paste the bearer token from developer.ttr.services.
5. The card is Active once an API key is stored.

The same per-state choice can be made on each State's edit page (drop-down Default - Use Sprwt Zipcode System / TTR - (Colorado API)); the card is simply a faster way to set many states at once.