"to Make one's oneself at home" means "don't be shy", act as you would in your house. It is a friendly saying. For example someone might say "Take off you coat, have a seat. Make yourself at home". The host is trying to make their guest feel welcome in their house. "to Make somebody feel at home" means to make someone feel comfortable and relaxed in your home. If your friend comes to your house, you would want he or she to feel welcomed and comfortable.