1.Search for the item and visit the record page

2.Copy the identifier for record , for example if the url is https://archive.org/details/b29000427_0001/page/n13/mode/2up then the identifier is b29000427_0001.

3.Place that identifier into the following URL structure: https://iiif.archivelab.org/iiif/<identifier>/manifest.json. For the example in (2.), the manifest URL would be https://iiif.archivelab.org/iiif/b29000427_0001/manifest.json.