RS,
Very good, and very close.
8Balls, you should plan your flight as per ERSA. The STARs are designed to link with the flight plan tracks into those aerdromes that have them.
If you don't plan correctly, the controller responsible for issuing the STAR will reclear you to the first point and then the applicable STAR.
The controller responsible for issuing the STAR depends on your level and route. For jets, this would be the enroute controller responsible for the airspace about 160 - 200NM from destination.
if there was a change of runway or inbound direction rendering my planned STAR unworkable, where and who can I get the new STAR from? Is it with Approach or something further like with Radar ?
If a change of STAR is required, the controller controlling you at the time will advise you and ask if you can accept a new STAR. If you can't, then an ammended clearance with an expectation will be issued. E.g. "Cancel STAR, track Blaka JCW BN, expect radar vectors from JCW"
If I did not nominate a waypoint for a STAR, will I be given one or will I be radar vectored instead for an instrument approach ?
When applicable you will be given a STAR. The STAR will link to your arrival (visual approach or instrument approach). If you cannot accept a STAR, then expect an ammended clearance and radar vectoring for your approach.
Hope this helps.