LINE WORKS

Hi, I'm new to line works and I am developing an application using this api. I would like to ask few questions in Organization Integration > Member. 

1. How do I can set the records to show all ? As you may know in  Request URL = 

                 https://apis.worksmobile.com/r/apiid/organization/v2/domains/123/users?page=1
       There is a querystring page wherein it is required. I want the record to be shown all.  How to achieve that?

2. How to apply the search functionality in Get Members? As you may know in  Request URL =

                 https://apis.worksmobile.com/r/apiid/organization/v2/domains/123/users?page=1
        The request url provided is not detailed enough for the search functionality. I have read in response the 

        Property Name searchable(Indicates whether to enable auto-complete and search for the member.) but how can Iimplement this?
        For Instance I want to search the name of the users in group of lineworks.

3. How does externalKey created? Assuming I want to add a Member? On what part does external key is being set/created?

Thanks and looking forward to your response.