Okay ! Well I think I know the step you missed so I will try to make it a bit easier with some visual aids : )
So the steps we're covering are these;
<blockquote class='quote_blockquote'><dl><dt>2. INSTALLING PATCHES:</dt><dd> </dd></dl><div>2.1 Copy Data folder over to your World of Warcraft install directory (e.g. C:/WoW/) and accept overwrite/replace if required.
2.2 Launch the client through WoW.exe (you can create shortcut of it and use that instead).
2.3 If the client doesn't crash, then client installation is successful. Move to connection (3. section).[/quote]
So the first step is moving the Data folder from the .7z folder we had you download at the start called "WoWFreedomMoP_548_Solution1_20150804.7z"
and then drag it in to your World of Warcraft: Mists of Pandaria client.
<div class='spoiler_toggle'>Spoiler: click to toggle</div><div class="spoiler" style="display:none;"><IMG src="http://i.imgur.com/5Zd6jvz.png"><s>[img]</s>[url="http://i.imgur.com/5Zd6jvz.png">http://i.imgur.com/5Zd6jvz.png[/url]<e>[/img]</e></IMG></div>
Once you've done this, you may possibly get a pop-up after soon enough that asks you this.
<div class='spoiler_toggle'>Spoiler: click to toggle</div><div class="spoiler" style="display:none;"><IMG src="http://i.imgur.com/3FinphL.png?2"><s>[img]</s>[url="http://i.imgur.com/3FinphL.png?2">http://i.imgur.com/3FinphL.png?2[/url]<e>[/img]</e></IMG></div>
Just click to replace the files and once everything is done being moved to the client, open it up check if you're on the right patch.
If you did patch up ! Awesome you should be good to go.
If it didn't patch up <E>
</E> make sure you didn't drop the "data" folder from the .7z in to another folder.
( You need to drop it in to the main folder don't drag and drop it directly in to the "Data" folder drop it some place to the side like I show on my screen shot. )