DC2 Tax rate configuration DC2 - latest 
I have promotions (discounts/coupons) working so can see adjustments etc.
I have set up a custom tax type - 20% and territory - UK
set values on my Order item types (Physical goods, Digital goods,Services,Events)
* How are these values related to assigning tax on a product in cart?

I can add a tax manually via order UI as admin.
I'm not seeing tax entries on checkout, and no tax entries in adjustments table (other than manual one).
* How is link between tax and order made?
thanks
Answer to second question is that the tax cannot be calculated until Billing address is present (as depends on 'territory' of store &amp; user) - so tax line is not seen initially until user reaches review stage.  Once the tax (as an 'adjustment') is added to order, it then stays visible - eg if user goes back to cart to add/remove items. The tax value then gets updated to reflect new cart contents on clicking 'Update cart', or clicking Checkout.