First off, how many emails will there be? Depending on your web host and server ti out intervals, it may be difficult to send to a large list. Web assist has mentioned here that for that reason it's really not meant to send in such bulk, although it will work if the server allow it.
You need a form on a page basically with only a submit button. Create a recorset on the page that contains all the email addresses. You said you have them in two columns - I'm assuming it's the same email address in each column, but you'll only need to use one column.
Open the UE wizard and enter all the necessary info like mail server, subject line, from, and your content for the email message. There are a few different ways to create the email content, read the support files and tutorials for this.
For the "to" field, you'll be able to choose the email column from the recordset and specify to send once per entry, so it loops through all the email addresses and sends the email for each one.
Again, depending on the size of your list, you may have problems. It can take several it's to loops through a large list, so specify a redirect page. When that comes up you'll know it worked. However, if you get an error, then the server may have times out - and yo will have sent to some of the list, but not all, and there's no way to know where it stopped.