1. Find the Bundle you want to add a restriction to
2. Scroll down to restrictions and click Add restriction
3. Choose the bundle group that contains the items you want to apply restrictions to
4. Select all the items you want to add restrictions to
5. Click on Next
6. Select the modifier group where the restriction will be set
7. Choose which modifier you are going to lock so the user cannot choose any other modifiers in the group when adding this item to their combo/bundle
8. When you finish click add restriction
9. Then Save the bundle