When you create a bid package, you will need to attach all of your bid documents in one folder in the Documents tab (e.g. ‘Bid Documents’). Underneath this folder, you can create unlimited subfolders for each bid package and upload the relevant documents into each. (Note: Only folders and sub folders that have files in them will be available to download using the download link in the invitation email.)
Your folder will need to be public (i.e. not marked "Private" and only available to 'Admin' level users and those you specify). If you try to attach a private folder to a bid package when editing it or creating it, you will be prompted to attach a public folder or to go back and mark the folder public or "unlocked".
Or, in the Bidding tab,