You are probably here because you have downloaded (or want to download) a program called Apprentice, and want to use it to play the Yu-Gi-Oh TCG online.

Links section:
Apprentice is originally a Magic the Gathering Program, but with a patch you can use it to play ANY TCG. this includes Duel Masters/Pokemon in case you are wondering. The next part of this page will be installation instructions for Apprentice.
When you run apprentice first time, you will probably get a info box that says "Silver is not a valid integer." Relax, here is how to fix that error:

Way 1: close the window, and open Options --> Prefrences, and switch to the third tab. now use bottom button to load a theme.
Way 2 (only use if Way 1 doesn't work): Open the folder that contains "Appr.exe", and delete "Appr.ini", then load apprentice again.

Section 1: Fresh Apprentice installation
(this section assumes you have downloaded Apprentice here)
Open your favorite Zip utility (Winzip, UltimateZip, etc), and open from wherever you saved it. Now unzip the ENTIRE patch to C:\apprentice\: (once you have set the options in the red and purple ellipse's, hit the button in the blue one)

Skip ahead to section 3 now....

Section 2: Patch installation
(this section assumes you have downloaded the patch here)
Close Apprentice, and open your favorite Zip utility (Winzip, UltimateZip, etc). Open the patch from wherever you saved it. Now unzip the ENTIRE patch to wherever you installed Apprentice previously (once you have set the options in the red and purple ellipse's, hit the button in the blue one).

Section 3: Creating a Deck, and Dueling with it:
Here is the meat of this guide. Hit File --> Deck Editor (or hit Control + K). You are greeted with the following screen:

The top half contains your searching tools, any YVD players should be familiar with most of them :P
The lower two drop boxes control the set and rarity search respectively. the one on the top you should neve have to use. In the Power/Toughness box, you can search for a specific Attack value by using "1900/"; specific defense value by "/1900" and of course, a combination of the 2.
You use the flavor text box to search for specific card types: Use "spell" so search for spell cards, or "trap" to search for trap cards. Monster cards can be found by entering the attribute in the card type box. To search with your given terms, hit "go".
To add cards to your deck: select them in the left hand side of the bottom, then hit "Add" to bring them over to the right side. Make sure you have a legal deck, and when you are done, hit "save" up top to save your deck. You can load decks for editing by hitting "load".
Once you have made your deck, save it and exit the deck editor, it is time to Duel! (remember to follow the restrictions at:!)
Now hit Control + N (or select File --> New Game) to be taken to the deck selection screen:

Of the red options, only "Sideboard" needs new explanation. If you had added 15 cards to your Side deck in deck editor (using "Sideboard" option instead of "Add") you could exchange cards in between duels. You load a deck using "Load deck" and it appears in the big box for you to view.
Of the blue options, they should always be set to "8000", "0", and whatever respectively.
Click "Ok" once you are set (be sure to select "Connect via the Internet", and be taken to the next screen:

Quick rundown of the new screen: Enter the agreed upon port in the red area. Use the blue/purple areas for You calling/Opponent calling respectively.
If you are waiting for a call, press "Ok" before you give opponent your ip. if you are calling, make sure opponent is waiting before you hit ok, and that their ip is entered correctly.

Have fun! For your first duel, look for somebody to show you stuff like the setup of the field and what not.
TIP: Apprentice IP (ie the IP that it displays) is usualy wrong. Find your IP another way.