What can be concluded from a full application of resolution?
By definition if a proof system is refutation-complete then once you've applied it to the maximum extent and not found a contradiction, you have proven that there are no refutations, i.e. the formula is satisfiable.  To find a satisfying assignment, add a unit clause that asserts a value for one of the variables, e.g. $(a)$, and use resolution on the resulting formula.  If you find a refutation (produce an empty clause), then replace the asserting clause with its negation e.g. $(\lnot{a})$, otherwise leave the original assertion in the formula.  Repeat the procedure with a different variable.  Eventually you'll have successfully asserted values for all the variables and found a satisfying assignment.