Create Router Instance
This operation creates a new router instance as a child from an existing router instance. You can perform this operation by right clicking on the router instance where you want to create the new one: 
In the image below you can see the form to fill. In the first page you can modify the information about the user. 
In the second page you can select the interfaces to add to the new router instance. You can select an entire physical interface or just select some subInterfaces. You also have to enter the name of the new router instance. 
When all the information has been entered, just click on 'Finish' to perform the operation.
Remove Router Instance
This operation removes a router instance from the database. You can perform this operation by right clicking on the router instance that you want to remove: 
If the router instance selected has other router instances as children, the following wizard will appear asking you if you want to delete also the configuration of the router children (the router parent and the children will be removed from the database and all the children will be also removed from the configuration of the router parent) or to keep them (the router parent and the children will be removed from the database, but if your discover again this router, it will still contain the children routers). 
If the router instance selected is a child of a physical router or it is a physical router with no children, the following dialog will appear to confirm that you want to delete the router instance from the database. If the router is a child of another physical router, the configuration of this router will be delete from the router parent. 