The asset class is the main criterion for classifying assets. Every asset must be assigned to only one asset class. Examples of asset class are Plant& Machinery, Furniture & Fixtures, Computers etc. The asset class also contains the Gl accounts which are debited when any asset is procured. It also contains the GL accounts for depreciation calculation, scrapping etc
Whenever you create an asset master you need to mention the asset class for which you are creating the required asset. In this manner whenever any asset transaction happens the gl accounts attached to the asset class is automatically picked up and the entry passed. You can also specify certain control parameters and default values for depreciation calculation and other master data in each asset class.