Checking Collective Availability Online 
The overall profile specifies whether process orders and/or planned orders are read. You can change the profile defined in Customizing temporarily using the ‘Object selection’ function.

For performance reasons, you should restrict the objects to order headers and components. If you do not need to display the individual order components, you can also exclude components from the selection.
The system lists the selected orders.
A dialog box for the availability check appears. You can use the Check mode function to call up another dialog box in which you can specify further parameters to determine the availability run.
The system checks the availability of the orders selected.

To display the availability log for a process order, select the order, and choose Goto