This support forum is for High-logic products, not MS products. I think you expect too much. I already told you what to do. If that’s not enough, read the help file for the Keyboard Layout Creator. Creating composites is explained in the linked tutorial thread.
For dot below I use Ctrl Alt . as a dead key. .ḍ ḷ ṃ ṇ ṛ ṣ ẓ etc.