You can create a new BOM without uploading a file. This is helpful for example when needing to copy and paste a few parts, or wanting to compile an ongoing list.
From your BOM Insight dashboard, click on the +Add New BOM button to create your new list. The accepted file types include .csv, .tsv, .xls, .xlsx, Eagle .sch, KiCad.sch, and .SchDoc.
This will take you to BOM Upload page. To continue without uploading a file, on the Settings tab skip past the "Choose BOM File" step. Do not select a file to upload.
Type in your BOM Name, select your desired Risk Index, enter Multipliers as needed; and then click on a project to use the Select Folder to store your new list there when applicable. The Description field is optional.
When ready, click on Next: Cost Prioritization to continue to the next step. This skips past the Mapping tab in the process, which is only utilized when there's a file.
More information is available in this article about BOM Cost Prioritization.
The rest of the BOM creation process is the same as when uploading a file. Click on Save to complete the creation of your BOM.
After your new list is saved, you can add parts manually to your BOM.