How do I examine the Crime Scene during the "Blood on Ice" quest in Skyrim?

You are supposed to follow the trail of blood

It will eventually lead to a house where you can find various pieces of evidence.

Follow the blood trail to Hjerim (the name of the house) and pick the lock (master). You can also go to the steward and he will tell you where to get the key to the house.

I watched this youtube video and followed that exact path to reach the clue house as I was not able to find it even after reading the spoiler in the accepted answer.

If you are running Skyrim on a seven year old laptop using a dozen performance mods, most likely, you won't see the blood stains.