Hi Raveena, 

The APIs are well documented with both the input and output parameters being defined in our online help

For your example, you can find the parameter definition here

https://help.pyramidanalytics.com/Content/Root/developer/reference/APIs/REST%20API/API3/dataSources/addRolesToItemAndBubbleUp.htm

the input parameter for this API is defined further here

https://help.pyramidanalytics.com/Content/Root/developer/reference/APIs/REST%20API/definitions/ItemRolesToBeAdded.htm

the itemId is to defined the starting point of the bubble up, and has two main usage cases 

1) To start from a semantic data model and bubble up all the way to the source, you need to put the model's ID into the itemId property and fill in the databaseId and the serverId with the relevant values.

2) To start from a database and bubble up to the data source, you need to put the database id into the itemId property and fill in the serverId with the relevant data source id. 

 

I hope this helps

 

thanks

Mark