For language professionals
As a native speaker, you have valuable knowledge about your language and culture which is important to language learners. When you offer native speaker conversation, you are opening yourself up to meeting language learners who need real world practice.
This real world practice will take the form of approximately 10-minute conversations. These language learners are learning about your language and culture and will be the other partner in the conversation.
You will be expected to help carry the conversation, and help your language learner with vocabulary and grammar that they might have an issue with. This can be done simply with the everyday vocabulary you use, no need to keep a thesaurus on your person. You may be asked to help someone with a specific conversation type, such as acceptable workplace vocabulary and grammar. On the whole, you will likely discuss common topics of interest.