In Step 1 (Learn) you addressed cultural differences by reading and reflecting on Contrasting Cultures content. In Step 2 (Discuss) you and your colleagues gained deeper understanding about those differences by engaging in three conversations.
Now, in Step 3 (Apply) you and your colleagues will discuss and decide how to improve collaboration. As in Step 2 (Discuss) there are three conversations:
Specific to the selected topic, reflect on the current state of collaboration. Recommend how the two cultures can better collaborate. Share those recommendations with your colleagues from the same-culture. They will do the same with you. And your colleagues from the other-culture will do the same on their side.
Reflect on the recommendations submitted by your same-culture colleagues. Then meet as same-culture group. Discuss the submitted recommendations. Decide which of them should be discussed with your colleagues from the other-culture. Then share those recommendations with them. They will do the same with you.
Reflect on the recommendations submitted by your colleagues from the other-culture. Then meet as both-cultures group. Discuss the submitted recommendations. Decide which of them should be implemented. Modify as needed. Now implement, learn, tweak, implement, learn, tweak, etc.
These Questions & Suggestions might be helpful.