Your router makes no difference. It's quite a simple process:
1) Switch on all clients. Log in to the admin account on each.
2) Run the Network Setup Wizard (not the wireless one) on every client in turn, applying common settings to each (ensure that your workgroup name is precisely the same). Choose to enable file and printer sharing.
3) Configure each client's firewall to allow two-way (or one-way if you want to keep certain clients private) access over the LAN (using each adapter's IP range). Ensure that these protocols go into the trusted zone. If you have a decent client firewall, it should flag up the new network communication when it first occurs and ask for a rule to be created. For this reason, it is a good idea to have each client attended during setup.
4) On the printer host, open Printers and Faxes, r-click your default printer and choose to make it shareable.
5) On all other clients, enter Printers and Faxes, choose Add a Printer and run through the simple wizard, choosing to use a network printer and browsing to its network location.
Job done. Now, all you need to do is create some shares on each client.