iPhone/iPad Download:
1. Tap link(s) sent by email after purchase.
2. Wait for file(s) to finish downloading on browser.
3. Tap anywhere on (Safari) screen & choose 'Open in iBooks' to add in iBooks.
Computer Download:
1. Right click link(s) sent by email after purchase.
2. Choose 'Save Link As' to save to folder of choice.
3. Drag downloaded PDF(s) to iTunes – Books – PDFs.
4. Sync with iPhone/iPad to add in iBooks.