1.I just read it and I will tell you in short.
The change of Qiblah took place in 2nd Hijri(After two years when Muslims migrated to Madinah).
In Makkah, the place where Muslims prayed facing was Jerusalem.When they migrated to Madinah, they faced praying in the same direction for 16 months.Just then when Prophet(S.A) was leading his Asr prayer, he was ordered to face Kaabah and lead the prayer and it hence became the religious center for Muslims.
-from Islamiat for Students by Farkhanda Noor Mohammed
As it is said in this verse as stated above:
We see the turning of thy face (for guidance to the heavens: now Shall We turn thee to a Qibla that shall please thee. Turn then Thy face in the direction of the sacred Mosque: Wherever ye are, turn your faces in that direction. The people of the Book know well that that is the truth from their Lord. Nor is Allah unmindful of what they do.
2.For locating Qibla you can visit
and read this too from moonsighting.com:
Qibla from Sun
It is not advisable to determine Qibla using compass specially for Orienting Masajid. The following method which uses the sun is more reliable. It has been observed for centuries and reported in many books by Muslims around the world that two times a year the sun comes overhead above Ka'bah. This is observational fact for centuries, and is used to set the correct Qibla direction in places far from Makkah by Muslims for last so many centuries. Those two dates and times are:
May 28 at 9:18 UT
July 15 at 9:27 UT
When you observe the sun at these times (after converting it to your local time), you will be facing the Ka'bah giving you Qibla direction, because if there were a very high minaret over Ka'bah reaching up to the sky, then you will see it just like you are seeing the sun. Now, let us take a few examples. If you are in Islamabad, Pakistan (+5 hours time difference from Greenwich), the local time to observe the sun would be 2:18 pm on May 28, and 2:27 pm on July 15.
Similarly, if you are in Nova Scotia, Canada (-3 hours time difference from Greenwich), the local time to observe the sun would be 6:18 am on May 28, and 6:27 am on July 15.
If you are at a location that you cannot see the sun on the above mentioned two dates, then you can locate Qibla from the sun when it comes overhead at a point diametrically opposite of Makkah on the globe and look for the following two dates and times:
November 28 at 21:09 UT
January 13 at 21:29 UT
Face toward the shadow from the sun at these times (after converting it to local time) and you will be facing Ka'bah. If you can see the sun but cannot see the shadow, put your back towards the sun and your face will be towards Qibla.