what is the important things in designing rescue robot
If i am not wrong by belt you mean a transmission belt.?
Usual necessities for a belt to travel on is the pulley..Ones which you can easily model in solidworks. After that go to insert - Assembly feature- Click belt/chain.
Select your pulley systems and correct the orientations to suit your needs.
Do remember to check the option " Create a part " under the tab.
Sw will create a new part as belt..to which you can add thickness and material by extruding. Everytime you change the position of the pulleys hit refresh. SW will automatically update the belt references.