Parameter changes are specified using a struct variable having multiple fields, which is passed as an argument to the appropriate Gurobi function (e.g., gurobi). The name of each field must be the name of a Gurobi parameter, and the associated value should be the desired value of that parameter. You can find a complete list of the available Gurobi parameters here.
We should say a bit more about the ResultFile parameter. If this parameter is set, the optimization model that is eventually passed to Gurobi will also be output to the specified file. The filename suffix should be one of .mps, .lp, .rew, or .rlp, to indicate the desired file format (see the file format section for details on Gurobi file formats).