Help needed from ATC re: STARs

[Eight Ball]

Hi guys,

Was wondering if any ATC out there can help with a question regarding Standard Arrival Routes selection for a learner driver.

Here goes.....

Considering the direction I am coming in from, I would select a waypoint (and include it in my flight plan) for the destination that would be the first waypoint in a STAR having a final approach to a particular runway/s.

My first question is - 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 ?

My second one is - 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 ?

And lastly - in regards to heavies, I can only assume that they have pre-programmed their STARs into their FMC even before departure, would ATC change this for any reason ?

Much appreciated.

Eight Ball