To start, go to the site qrcodechimp.com
You need to create an account which is free. Once your account is created you can now make your own page that will be what your customers will see when they scan your QRCode
The contact details you can enter are extensive! Everything you put in here will be visible to the person who scans your QRCode. On the right of the screen, you can see what they will see on their device after scanning. Just one click and your contact details are all in their contacts list!
When your QRCode is ready, you can click download to get an image file. This is what will be used in your Card by The Card Project
The image here shows the defaults, you do not have to change these. The Card Project system needs the QRCode to have these settings
The file type is PNG, the size is 1024px. Using these settings will result in the QRCode being able to be scanned by the potential customer