Building on top of Nwada001 reply, SeedQR is a clever way of transforming your seed phrases into a single stream of digits. If you go over to the SeedQR documentation[1] you will quickly understand how it works, but to give you a quick idea:

• The total worldlist for seed phrases is 2048;
  
• Assume that your first seed phrase is "banner", which occupies the 147 position in the english wordlist[2]
• Your second one is "scatter", which occupies the 1540 position[2].
• The SeedQR specifications uses the positions of both seed phrases (0147 for banner and 1540 for scatter) and combines them (01471540). You would have to continue do this exercise until you have combined all 12 or 24 seed phrases into a single stream of digits.
  

Using this knowledge you now understand that you basically have to group each 4 digit from the single stream of digits in order to obtain the first seed phrase. You would have to keep doing this until you have the complete seed phrase list in your possession.

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[1]https://github.com/SeedSigner/seedsigner/blob/dev/docs/seed_qr/README.md
[2]https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt