...Modem – Motorola? Would a D-Link DIR-615 router work well on a SURFboard sb5101i - Cable Modem – Motorola?

I'm planning to buy a router since now got a laptop and a desktop pc. Also, I wanna establish a network between the two. Like sharing files from one pc to the other through the Ethernet connection. The desktop is Win XP SP3 and the laptop is Win Vista Home. How can I share files between the two...step by step instructions please. thanks.