I have apply glass material and sun is in the position everything looks good but no lights enter the room. I have added hdr file and a lamp. Whats the reason what im missing to get light enter the room. All black inside the room and just the hdr image is seen from the window. In the red mark there is no light. And in green mark where the edge is coming from as there is no wall. And from the window the background look so artificial.
This question is indeed a duplicate.
What you need to to do is change the glass material:
As suggested before: How to illuminate the darkness inside glass objects in Cycles?