When collecting an opportunity from a sales event it is of key importance that you use the 'Qualification' feature.
When you enter the 'Qualification' feature in the app it is mandatory to choose at least one product that the opportunity is/was interested in. This will help you in the follow-up process.
This is done by simply:
1. Click the opportunity that you want to edit
2. Click the 'Qualification' button
3. Scroll to the bottom on the page and mark at least one product
4. Fill out the rest of the blank fields in order to give the opportunity more value
5. Your opportunity is now qualified