Ah, I see! Your manifest file should be a file, not a directory. The contents of the file will be a CSV, with your sample IDs, paths to your fastq file, and the read direction. You will need to make the manifest file yourself --- QIIME 2 isn't able to infer most of that information on its own. Please review the section Fastq Manifest Formats (which appears to be what you have printed out in your attached photo) - this provides some background and guidance on how to prepare your manifest file.