I humbly submit this as a non-expert, end user because this information is spread across several RockRMS manuals and its easy to get confused.  As of version 9, there are three types of RockRMS-Twilio integration, each requiring three unique Twilio/WEBHOOK configuration URLS.   You essentially have to choose which one of all three features you want your ROCK/Twilio number to utilize.  One number doesn't do all three of these functions.

(Usage #1) For SMS CONVERSATIONS (i.e. SMS Message Forwarding) 

This feature allows an SMS number to spoof a staff person's real cell number. When a message is sent through RockRMS, each conversation is given a an id number [for example: (@123) ]. When a staff member replies with this conversation id number, RockRMS is able to send a response back to the person who initiated the SMS Text.

• -In Twilio, the inbound message must be set to WEBHOOK, HTTP POST, with the URL: [your website]/Webhooks/Twilio.ashx
• In RockRMS, go to Admin > Communications > SMS Phone Numbers and add the SMS Phone Number configured in Twilio and link it to a staff person's phone number.
• In RockRMS, go to People > SMS Conversations and select the phone number to manage. Send and receive messages as desired, or use your personal cell device if setup. 

(Usage #2) FOR TEXT-To-WORKFLOW (SMS Keyword Responses). 

This feature allows people to text an individual keyword to a RockRMS/Twilio number and receive an SMS Response. If a keyword doesn't match the criteria setup in Rock, the user receives a message that a keyword is not setup. Once setup, the Keyword can trigger a workflow, etc.

• In Twilio, the inbound message must be set to WEBHOOK, HTTP POST, with the URL: [your website]/Webhooks/TextToWorkflowTwilio.ashx
• In RockRMS, go to Admin > Communications > SMS Phone Numbers and add the SMS Phone Number configured in Twilio and link it to a staff person's phone number. 
• In Admin > General Setting > Defined Types find the Workflow type "Text to Workflow." In the lower section, add a new item that includes defined value/ description/ keyword expression/ workflow type/ workflow name template, and workflow attributes (see below).
• Study the "Blasting Off with Workflows" Manual to understand how to utilize the values in a workflow. 
• In the workflow, create a text field called SMSResponse. When a value is set to this field, the workflow automatically responds with that text.
• Online, you can google for a regular expression builder to help you come up with more complex matching patterns.  For example, this string will match upper/lower case words matching pattern serm.*      \W*((?i)serm(?-i))\W*

Defined Type Configuration: 

• The value is the phone number receiving inbound keywords (i.e. +1#######)
• The keyword expression is the keyword to watch for (i.e. serm.* watched for sermon, sermons, etc)
• The workflow type is the workflow to be triggered.
• All the workflow attributes need to be added if they are to be used in the workflow:
• FromPhone {{FromPhone}}
• ToPhone {{ToPhone}}
• ReceivedDate {{ReceivedDate }}
• ReceivedTime {{ReceivedTime}}
• FromPerson {{FromPerson}}
• MessageBody {{MessageBody}} 

(Usage #3) For SMS PIPELINE (Conversational Responses) 

This feature is similar to Text-To-Workflow but isn't limited to individual keywords that are managed by RockRMS/Twilio. For example, a person could send a prayer request to a RockRMS/Twilio number and it could be recorded into ROCK RMS.

• In Twilio, the inbound message must be set to WEBHOOK, HTTP POST, with the URL: [your website]/Webhooks/TwilioSMS.ashx
• In RockRMS, go to Admin > Communications > SMS Phone Numbers and add the SMS Phone Number configured in Twilio and link it to a staff person's phone number.
• In RockRMS, go to Admin > Communications > SMS Pipeline and build your conversation responses.
• When adding a Workflow to the SMS Pipeline, its configuration is nearly identical to the Text-To-Workflow setup.
• Online, you can google for a regular expression builder to help you come up with more complex matching patterns.  For example, this string will match upper/lower case words matching pattern serm.* \W*((?i)serm(?-i))\W*

SMS Pipeline Workflow Configuration: 

• The phone number is receiving inbound message (i.e. +1#######)
• Check Active, and/or Continue as indicated
• Setup your message (filter). You can use regular expression for more complext keyword matches (i.e. serm.* watched for sermon, sermons, etc)
• The workflow type is the workflow to be triggered.
• The workflow template is a user friendly label for the workflow [ i.e. Request From {{FromPerson.FullName}} ({{FromPhone}}) ]
• All the workflow attributes need to be added if they are to be used in the workflow:
• FromPhone {{FromPhone}}
• ToPhone {{ToPhone}}
• ReceivedDate {{ReceivedDate }}
• ReceivedTime {{ReceivedTime}}
• FromPerson {{FromPerson}}
• MessageBody {{MessageBody}}