How do I restore networks to default?

Hi All . . . I bought an Epson WK 3540 printer last week. Before the purchase, the folks at Epson told me this printer would set up and run wirelessly using Airport 802.1x. That was one of the selling points. I have tried to set up the printer, but the computer does not acknowledge the printer. Previously I had an HP 8500 printer and the wireless set up went smoothly. I did not have to do anything special. I plugged it in and powered it up and my Mac saw it and life was great.
Since the Epson wasn't recognized, I went into System Preferences trying to see if I could set up a network so that I could install this printer. I tried to create and set up a network, but to be honest I had no clue as to what I was doing. I guess I was hoping to get lucky. OK...to the problem...I now have made a mess in my Airport/Networks system. It was asking for passwords and I kept trying different things on different networks. My computer is connected to the Internet by Ethernet cable. It is only one computer and I really don't have a network, router, or any other devices or iSTUFF that need to be configured. So how do I clean up and restore the Network section? I need to get rid of all the stuff I created and get my Mac back to where as if I had never messed with Networks. Can anybody help? Another question is why would the HP set up and install with Airport 802.1x by itself and this Epson won't do it? Where do I find all these passwords it keeps asking for. If it helps, under Airport it shows 0750, ASUS, shelby, and DDW36117B. I hope this makes sense.

Try connecting by USB in the first instances and when all is good try wireless hitting the WiiFi button on the printer. Go into System Preferences > Network > Advanced and delete preferred and any other networks. Use ethernet cable and set modem/router up using the URL and then set WiFi up again.

****, I love this forum. Thanks, harryb2448. I will get the USB cable tomorrow and try your solution. I appreciate your time and effort to help. I will follow up with the results.

BTW...All USB ports on the Mac are "occupied". I have a powered USB hub connected, but some things work best connected directly to the Mac (like my recording mic). The mic is not recognized when plugged into the hub, but when plugged into the CPU it works like a champ. Is there such a thing as a Firewire800 to USB cable? I Googled it and didn't see anything.

Well it was a four minute delay but with a username like that who could refuse?

...from harryb2448..."Use ethernet cable and set modem/router up using the URL and then set WiFi up again." Sorry harryb, when it comes to networking, I am as dumb as my username. Would you please walk me step by step through this?
I should connect the ethernet cable from what device to what device? Where will I find the URL for the modem (no router) and I assume I will enter the URL into the WiFi set up on the printer when it asks?!?!?

Ethernet cable from modem to computer. The URL will be in the modem's user guide. usually something like 192.168.1.1 - simply open Safari and enter that into the address field and press enter. Most modems use admin as the username and password.

Select WPA2 Personal and proceed from there. If you pm me the brand and model of your modem will see if a manual is available online.

I'll pm that info to you as soon as I can get to it physically. The "cable guy" didn't leave any kind of manul or documentation upon installation of the modem. Thanks for the help.