I've been able to merge the BSP and Sinbad code and found out that both the Ogre and BSP have different co-ordinate system. They work on different ideologies. So, what is happening after Google and Gemini help? I've discovered that Sinbad lands on Ogre Y axis if I make both BSP and the Ogre co-ordinates the same, then Sinbad lands on Ogre Y axis and walks on the Y axis plane, which is why I can't see anything. I'm looking at the sky.
The second thing I found out is that the Ogre Sinbad is very short in terms of size. I think it's like an ant compared to BSP maps. Gemini suggested flipping the map by 90 degrees by pitch, which is equivalent to the y-axis. Flipping Ogre 90 Degree lands him correctly, but then movement breaks or becomes laggy. How to do that and how to control the camera distance according to the scaling of the character. Thanks!