MIB Browser allows you to load MIBs directly. Whenever the files are loaded, they are compiled and then loaded.
Click the Settings -> Tools tab -> MIB Browser.
Select a MIB from the Select MIB combo box. The Selected MIB gets loaded below.
If you want to load a MIB that is not available by default, click the Add MIB button. In the Add MIB dialog that appears, use the Browse button to choose the MIB, and click the Add button. If a MIB has any dependent MIBs ensure that all the dependent MIBs are also added to avoid errors. Click Close to close the dialog. Check if the MIB that is loaded is displayed in the list box.