urls devs done

collections/developers/tfchain/dev_tfchain.md

@@ -68,7 +68,7 @@ Every contract is billed every 1 hour on the chain, the amount that is due is de
 - 50% goes to certified sales channel
 - 35% TFT gets burned
 
-See [pricing](../../../knowledge_base/cloud/pricing/pricing.md) for more information on how the cost for a contract is calculated.
+See [pricing](cloud@@pricing) for more information on how the cost for a contract is calculated.
 
 ## Contract locking
 
@@ -80,7 +80,7 @@ When the owner of a contract runs out funds on his wallet to pay for his deploym
 
 ## DAO
 
-See [DAO](../../dashboard/tfchain/tf_dao.md) for more information on the DAO on TF Chain.
+See [DAO](dashboard@@tf_dao) for more information on the DAO on TF Chain.
 
 ## Farming Policies
 

collections/developers/tfchain/introduction.md

@@ -45,7 +45,7 @@ It is the backbone of [ZOS](https://github.com/threefoldtech/zos) and other comp
 A twin is a unique identifier linked to a specific account on a given TFChain network.
 Actually there are 2 ways to create a twin:
 
-- With the [Dashboard](../../dashboard/wallet_connector.md)
+- With the [Dashboard](dashboard@@wallet_connector)
   - a twin is automatically generated while creating a TFChain account
 - With the TFConnect app
   - a twin is automatically generated while creating a farm (in this case the twin will be created on mainnet)

collections/developers/tfchain/tfchain_external_service_contract.md

@@ -2,10 +2,19 @@
 <h2>Table of Contents</h2>
 
 - [Introduction](#introduction)
-- [Step 1: Create the contract and get its unique ID](#step-1-create-contract--get-unique-id)
+- [Step 1: Create contract / Get unique ID](#step-1-create-contract--get-unique-id)
+  - [Create service contract](#create-service-contract)
+  - [Last service contract ID](#last-service-contract-id)
+  - [Parse service contract](#parse-service-contract)
+  - [Wrong contract ID ?](#wrong-contract-id-)
 - [Step 2: Fill contract](#step-2-fill-contract)
 - [Step 3: Both parties approve contract](#step-3-both-parties-approve-contract)
 - [Step 4: Bill for the service](#step-4-bill-for-the-service)
+  - [Send bill to consumer](#send-bill-to-consumer)
+  - [Billing frequency](#billing-frequency)
+  - [Amount due calculation](#amount-due-calculation)
+  - [Protection against draining](#protection-against-draining)
+  - [Billing considerations](#billing-considerations)
 - [Step 5: Cancel the contract](#step-5-cancel-the-contract)
 
 ***
@@ -19,12 +28,12 @@ The initial scenario is when two parties, a service provider and a consumer of t
 This is actually a more direct and generic feature if we compare to the initial rewarding model where a service provider (or solution provider) is receiving TFT from a rewards distribution process, linked to a node contract and based on a cloud capacity consumption, which follows specific billing rules.
 
 The initial requirements are:
-- Both service and consumer need to have their respective twin created on TFChain (if not, see [here](tfchain.md#create-a-tfchain-twin) how to do it)
+- Both service and consumer need to have their respective twin created on TFChain (if not, see [here](dev_tfchain.md#create-a-tfchain-twin) how to do it)
 - Consumer account needs to be funded (lack of funds will simply result in the contract cancelation while billed)
 
 In the following steps we detail the sequence of extrinsics that need to be called in TFChain Polkadot portal for setting up and executing such contract.
 <!-- We also show how to check if everything is going the right way via the TFChain GraphQL interface. -->
-Make sure to use right [links](tfchain.md#deployed-instances) depending on the targeted network.
+Make sure to use right [links](dev_tfchain.md#deployed-instances) depending on the targeted network.
 
 
 # Step 1: Create contract / Get unique ID
@@ -55,7 +64,7 @@ Check if the contract fields are correct, especially the twin ID of both service
 
 ## Wrong contract ID ?
 
-If twin IDs are wrong ([how to get my twin ID?](tfchain.md#get-your-twin-id)) on service contract fields it means the contract does not correspond to the last created contract.
+If twin IDs are wrong ([how to get my twin ID?](dev_tfchain.md#get-your-twin-id)) on service contract fields it means the contract does not correspond to the last created contract.
 In this case parse the last contracts on stack by decreasing `serviceContractId` and try to identify the right one; or the contract was simply not created so you should repeat the creation process and evaluate the error log.