If it is within 24 hours of your Meet and Greet you should have received an email from  support@stagepilot.com that includes the link to join your Meet & Greet and your secret 8-digit code. 
Once you click the Meet & Greet link, you will be prompted to enter the 8-digit code. Please do not share your code with anyone as each code is only good for one Meet & Greet. 
If for any reason you need to switch devices, you are able to use your code on a different device, as long as you have closed out of the Meet & Greet on the first device. 
You can refresh the page or switch devices without losing your place in line.