Noorani Qaida Page 19,  lesson 11  is about sakin that appears above the letters. It has multiple words that you have to pronounce separately and then join them. It will guide about the bold letters and give a deep understanding of which letters are throatal letters. Furthermore, It also gives you knowledge about waqfa. Waqfa means where you should stop while reading Qaida and the Quran. If there is Meem then it is waqfa -e -lazim to stop and there are many other signs such as taa where it comes it means you have to stop here.