1.  Opem ModelSim
type VSIM

2. File->Change Directory to where your files  are.

3 Tools->ExecuteMacro
select file 

tb_muxdemo.tcl

CLICK OK

4. Use your  previous knoweledge on how use MODELSIM simulation:
simulate dislpay waveforms,....etc....
5. You will be able to see that the wavefroms correspond to the specification!