https://us.tamrieltradecentre.com/help/AddonAndClient?lang=en-US
Or read the description of the addon here:
https://www.esoui.com/downloads/info1245-TamrielTradeCentre.html

If you got any more questions please be more specific what you are trying and what you want to achieve as your post above somehow makes no sense.
You mean you have uploaded data of YOUR listed guild store items and want to find them on the wbsite/in the game?
You will only find them ingame AFTER some time has passed AND you have updated the price tables (your game needs to be closed at that time!) via the included client.exe file.
This is all described in the install and description info linked above.

Basically it works this way:
You list items in a guild store.
You can share the info with others by saving these listings to your live/SavedVariables/TamrielTradeCenter.lua SavedVars file.
You can upload them via the client or the website to share them with the website https://www.tamrieltradecentre.com/
You can use the client.exe to download a PriceList.lua containing the uploaded price data of all other players on the same server.
This needs to be done before the eso client is started and maybe even multiple times a day if you want to get the most recent/updated data.
Start the client, and the data should be available ingame then.

Almakor wrote: »

I rechecked the specifics of the add-on and learn it gives them my email address and other information. I have a long history of viruses, malware, and credit card fraud so now I'm worried about other possible problems.

If you are concerned, make an alternate email address and use that. They only use that and your game userID (which is visible to everyone in game anyway).

These days, everyone should have a "throw away" email that they can use for anything they don't 100% trust. I have two.

Almakor wrote: »

I rechecked the specifics of the add-on and learn it gives them my email address and other information. I have a long history of viruses, malware, and credit card fraud so now I'm worried about other possible problems.

Where does "the addon" got access to your email address?
The addon's client.exe file maybe needs it if you want to uplaod the listings of your guild traders to the website.
If you do not want to do this you do not need any account for the website and are able to just download the actal PriceTable.lua file via the client.exe without specifying any email or username or password!

If you want to uplaod data to the website you need the account as it seems, and that's how all websites with a user login/Account work today. Just create a fake email address and use it for such purposes e.g.

But the addon ittself does not use any email. Addons got no access to any email or other pc data.