Transaction Launcher in IC Webclient?

Dear all,

Why we use Transaction Launcher in IC Webclient Configuration? What is the use of it?

After creation Navigation bar profile, Trnasaction bar profile and Business Profile and assinging to IC weblcient profile, How could we call it into PCUI interface?

How many Interfaces does IC Webclient Supports?

What is the major differences between SAP CRM Winclient and Webclient?

Please help to understand the above scenarios clearely, your suggestions and help will be highly appreciated.

Thank you