Today, the 21st of June is being celebrated as the United Nations International Yoga day. If you want reference to a few basic aasanas, the government has released a booklet describing how to do these.
http://idy.nhp.gov.in/UploadFiles/files/jk_IDY%20common%20yoga%20protocol_book.pdf
However, it is always recommended to do this after training from a Yoga guru.