Try expressing ideas using all of the language and rules you've learned up to this point, especially the new vocabulary words and grammar structures. Follow the patterns given in the lessons and the footnotes, then replace the vocabulary with words from the supplementary lists. Make up your own dialogue, or talk to yourself or a friend in Chinese. Practice saying sentences to yourself as you go about mundane daily activities, such as driving, exercising, cleaning, etc. Take it slow and don't get overwhelmed at the amount of information contained in each lesson.
Language learning takes time and practice.