For example, what would you do if you had ten thousand dollars?
Literal
For-example you [subject-が] 10,000 dollars hold-ていれば how-would-do [probably-だろう].
例えば ('for example') is adverbial. 持っていれば is the conditional ~ば of ~ている ('if you were in a state of having'). どうするだろうか forms a hypothetical question: 'what would one (probably) do?' The だろう here softens it as a musing, not a direct demand.