Tickets can be redeemed manually on laptops or your volunteers can download a free QR reader from either the iTunes app store or android/google apps. (I just downloaded the first free one that popped up for my phone...mine is made by TapMedia)
Here are some other options:
Here is a ticket your volunteers can practice with. It can be scanned over and over and it won't be redeemed. After you click the link to open it, you can scroll down and choose if you want to open a PDF ticket (for printing) or if you'd like to have the ticket texted to you.
This is what the ticket looks like:
To redeem open the QR reader on your phone and make sure the entire code appears inside the brackets. (My QR reader is so fast I can't take a screen shot so pretend the QR Code is inside the brackets below).
When the code is read, this screen will apear:
The scanner needs to hold the redeem button down for a few seconds- just to protect against early redemption. Once the ticket is redeemed it will turn green:
The guest will then be automatically joined to the event and will get a welcome text with a link to auction items (if your event has an auction or raffle).