For your first function, you don't need to do anything with Twilio. I presume you want to parse an XML feed to get specific data from it.
You can use a gem like nokogiri to parse XML, have a look at this similar SO question to learn how:
Parsing XML with Ruby
There's tons of other resources on parsing XML using ruby here to:
https://www.google.ca/search?q=parse+xml+ruby&rlz=1C1CHFX_enCA552CA552&oq=parse+xml+ruby&aqs=chrome..69i57j0l5.3359j0j7&sourceid=chrome&es_sm=122&ie=UTF-8
For your second function, this is where you'll actually be using Twilio. First off, I'm assuming you've setup Twilio, if not, head over to and sign up:
https://www.twilio.com/
You'll want to add the Twilio ruby client in your Gemfile:
gem 'twilio-ruby'
Be sure to bundle install and if everything is good, you are ready to code your Twilio interaction. Assuming from fn1 you have the data in a variable, you'll now need to send it via SMS/MMS, here's the Twilio guide for that:
https://www.twilio.com/docs/quickstart/ruby/sms/sending-via-rest