There’s no “temple” or other place; often shamans will practice in the home of their patients, or in their own homes. A public ritual may be held in the middle of the village.
Read these if you want to know more about shamanism:
http://lupabitch.wordpress.com/category/shamanism/ (some book reviews)
By the time you get done with reading these pages and a few of the books recommended in the last link you should at least have a beginning idea of what shamans do and how people become shamans. It really depends on the culture.