Rav Nacson’s Laws of Niddah is a great, concise Kitzur halachot of all the necessary Halachot according to Hacham Ovadia with great footnotes to all the Hacham Ovadia Torah among other popular Sefarim. He intentionally doesn’t spell out every detail like Hacham David, so the sefer is much more manageable to get through. Plus, he includes sample calendars and charts to better grasp the concept of vestot. Finally, he has a review test at the end to make sure you didn’t miss anything.
"As be has done in his previous books, he has delved into the words of the Rishonim and Acharonim, and has explained their words with good language and with absolute clarity" Rabbi David Yosef, Rosh Kollel of Yechaveh Daat, and author of Halachah Berurah