How do I hook d link up to my comcast router so

Connecting your WBR-1310 is not difficult, really. The router has a connecxtor labelled "WAN" on the back side, and 4 additional connectors. Your Comcast modem has a connector on its back too. Use a CAT-5 cable between the Comcast box and the WAN input on the WBR-1310 router. Plug another CAT-5 cable into any of the 4 connectors and the other end into your computer's Network Card's RJ45 connector. This is the easiest way to put your router through its setup. Accessing the router is done with the web address of 192.168.1.1 ... you will need to log in to the router as an administrator, usually with the login of User Name Admin, and a blank password. If you still have the documentation that came with the unit the login may vary.
Anyway, in Setup you decide the SSID (name of your network) and set up any security you may desire. I personally prefer WPA-PSK[TKIP] on the Wireless setup page. After that is done, your wireless internet should be done. You will need whatever password you set up to get your` wireless to log in.

I am not a comcast customer, but I have a friend who is, so I have the impression they are a very user-friendly ISP. Maybe their router can be replaced with your wi-fi one, so that the setup will be less complicated. They may not like when/if they find your second router, installed w/o notice. If you do a mistake you can block the line fir your neighbours...
But since you ask for an advice - the LAN cable coming out oof comrut (now probably connected to a PC) should be connected to the WAN of dlinkrut Then you can connect wired PCs to any of the free LAN ports of the two routers (six?). As per software configuration, use the router's manuals. Have in mind it is quite complicated tho. http://portforward.com/ may help you.

Well, you are trying to connect a router to a router, that can be difficult. Is there anyway you can exchange the Dlink router for a Wireless Access Point (AP)? If you can, you just connect the AP to the 4-port network side of the comcast router, configure the wifi settings (security, etc), and you're good to go.
If you can't exchange it, then your best bet is to connect the 4-port (or internal) side of the dlink router to the 4-port side of the comcast router. Then the dlink will be seen by the comcast router as another internal connection, and you can set the wifi settings of the dlink at that point. If you connect the dlink to the comcast router via the External port on the dlink, then you are creating two separate IP subnets, a needless complex setup.