For any post, you can simply click on the post and start a private conversation with the person. If you have already chatted with a person, but removed the conversation from your conversation list, you can start a new conversation by clicking on any post from the author again.

By clicking on a private conversation for a long time, you can block the person. They can no longer write privately with you and you can no longer write privately with them. For both conversation participants the chat messages are then also not visible. You can unblock the person again by clicking on any of the author's posts again and then click unblock.

Best regards from the Studo Team