Advice on modeling user interface use cases

I’m designing an application and I would like to have some advice in which is the better way to model some use cases.
The application will have a user interface which will enable users to perform two generic kind of operations. Once the user selects one operation, the application will show a list of possible suboperations to perform.
This is the typical scenary of a web application.
I’ve modeled this with two use cases, one for the global operation 1 and another for the global operation 2. The user actor has a direct association wich each use case. Then each use case includes a use case for each possible suboperation. When describing the global use cases main flow, I select each suboperation use case depending on what the user selected. For example:

Global Operation 1 Main Flow:

<> suboperation1 if user selected…
<> suboperation2 if user selected…

I’m not sure if this is the best approach and if the global operation use cases should include the suboperation use cases or the suboperatio use cases should extend the global use cases.

Thanks in advance.