A newbie's question to correct/edit tags

I am sorry if my question sounds silly! I am very new here. :rolleyes:

I have my mp3 files (all albums in separate folders. I drag and copy these folders to my Sansa players. These mp3 files are both legally purchased from Amazon and ripped from my own CD's.
When I scroll the artists on these players, I occasionally see "Unknown artist"!!!
As many people recommend mP3Tag, I want to be able to use it correctly.

I installed the software and launched it. Then, clicked File/Change Directory.
All the files are listed alphabetically. :flushed:
So, my question is this:

Is it possible to drag few albums (folders) into the panel and check the tags to see whether or not they need to be corrected? This way I have total control. I don't care how long it takes to check each folder.

When a folder or folders are in the panel, what do I click to check them thru Internet?

Thank You.

Is there a pdf help file to download and use with mp3tag?

You find more information on MP3tag in this forum and in the help:
http://help.mp3tag.de/
(or press F1).

Files are sorted according to the sort criteria.
To sort the file list by album, first click on the column header for TRACK and then on the column for ALBUM.

For checking data you find sources in the Web Sources menu.
Also, there is a collection of other web sources here in the forum for download:
/c/web-sources-scripts