Hosting a TCP UI

Anyone can host a UI. TCP provides an open source UI that anyone can use as is, or fork and adapt however they wish.

Build your own ui, or fork the ui. Modify it however you want, or leave it unchanged.
Register a UI by calling accounting.registerUI on the Accounting contract from the address that you wish rewards to go to. This ensures that the incentive destination address is accessible, and TCP sent there won't be lost. Be sure that the transaction completes.
Call accounting.nextUserInterfaceID on the Accounting contract.
Subtract 1 from the result of nextUserInterfaceID, and input that number into the accounting.userInterfaces function on Accounting. Check to see that the information matches the User interface you just registered. If not, repeat this step by subtracting one again until you find the interface you registered. This is your UIID!
Ensure the UI that you host sends this UIID with all transactions that touch debt positions or liquidity positions. From the open source UI, this simple means updating the UIID constant to your UIID.
Deploy your UI to IPFS. This as an exercise for you to figure which of the many easy to use services you like. Otherwise all TCP UIs would all end up on one service, and that isn't very Trustless, is it?
Once you have your IPFS hash, call accounting.initializeUI with the UIID, and the IPFS hash. as soon as you do this, your ID will show up <here> for the world to see and use!