Cut the wires leading to the key and if there is only 2 you should be able to recreate the currency of a key and start it up.
you use the kickstart usaully
Most dirtbikes are kickstart, where you kick down on a lever.
does a dirt bike come with keys
No, you kickstart it
Yes it has, but that depends on where are you located... For example in Colombia that bike comes with kick start, but in USA comes with electronic ignition
top end is blown deffinetley
No, the magneto provides the voltage for the spark.
Most bikes have kickstart on right. Older bikes from 80s and before may have left or right, and on less common brands like ktm, husqvarna, etc
That depends on what you are using it for. Obviously, if you are dirt biking, you should use a dirt bike, and otherwise use a street bike. Start out with what you are going to use the most - dirt (freestyle) or street racing.
It may have been run without oil and you blew it up.
Your engine could be locked up from low oil, burnt up rings or just a blown up engine
First make sure the bike is in neutral and push kick start down on right side of the bike.