Hello im planning on building a featherweight robot with a spinning disk on the front

Here is my rough drawing



I know the design is basic but I just want to get to grips with building my first robot :P

i am thinking of buying the following from robochallange
12v motor/gear box combo with holders
100mm wheels
battle switch for the disk?
Im not sure what speed controller or batterys I need, any ideas on these or what else I need??

Thanks in advance