Currently, leases are classified as operating or capital (financing) leases. Operating leases are treat as a "true lease" meaning that you have temporary use of the asset but not a substantial array of the rights of ownership. Capital leases convey most of the rights and privileges of ownership and so are accounted for as purchases with financing rather than true leases. That is, the "rents" are treated as principle plus interest payments on a loan used to purchase the leased asset. The asset purchase price must often be computed ...
Your tutorial is 327 words plus a reference and discusses operating versus capital / financing leases and off balance sheet treatment.