Hey,
You can't access the asset automation from the asset model. In order to automate the assets, you can go to the Configuration menu and select the Chart of Accounts. And select the depreciation account you mentioned in the asset model. Now you can edit the configuration of this particular account that you selected as the depreciation account.   

Here, you can find the Asset Options under the Automation tab. The Automate Asset feature will help you to automate asset management. You can set it as No, if you don’t want to create and validate assets automatically. Selecting the Create in Draft option will create a draft asset automatically as soon as you validate the bill. Later, you can validate the draft asset manually. Odoo will automatically create and validate assets when you select the Create and Validate option. The asset will be in the Running state once you confirm the bill. Enabling the Manage Items will let you manage multiple quantities of assets at the same time. The Asset Model you selected will be available in the respective field.