Uploading Multiple Files

Build a deck incrementally by uploading multiple CSV + YAML pairs:

1. Upload first pair → first set of blocks renders
2. Upload second pair → blocks append to the bottom
3. Repeat as needed
4. Print to PDF when done

Set block_starting_number in subsequent YAML files to maintain continuous numbering. If the first config renders 8 blocks, set block_starting_number: 9 in the second.