If they're setting up their own customer.io account first have them go to customer.io.

Have them signup for the trial and go through that process.

Once the account is made you'll see this screen. We're Finished with the initial setup.

Follow this guide for creating a Segment account and setting up the source.

Next, we'll add Customer.io as the destination.

Click "Add Destination". Search for "Customer.io". Once you find it click "Next". Then choose your "Source" and next and name the source Customer.io. Click done once finished.

After It's created double click on the "Customer.io" destination.

Click on "Site ID**"

Go back to Customer.io ->Click "Data & Integrations" ->Integrations->Search for "Segment Destination"->Copy the Site ID and paste into Segments Site id and save.-> Do the same thing for API Key. Then click on the "Activate" button.

Then that's it! Now to make sure it's sending information go to segment->Click Connections(top right)->Click your "Source"->Click "Debugger" and you should see "IDENTIFY" and "TRACK" events being sent. Next, we can confirm this is working on Customer.io's side by clicking people.

Next, we need to configure their DNS to support sending emails. Open up Customer.io->Settings->Workspace Settings->Email->Add Sending Domain->Add their website to the Domain you can skip the other 2 fields below-> Once Created click "Manage Domain" and Copy all the seconds or tell them they need to add these records to their website DNS. Once added we can click "Verify Domain" but it might take a while to verify after they add the records.

Next, we need to configure their SMS to support sending emails. Open up Customer.io->Settings->Workspace Settings-> Twilio SMS-> They'll need to buy a new number in Twilio and follow this guide.

Once that is set up input their "Account SID" and "Auth Token" and you should see several numbers below.

Now we're finished!