This is a Step by Step guide on how to get an account AND download-install the game.
First you're obviously going to need the account. Doesn't matter if you download and install you still need an account to play. Before I bought this I looked up reviews and if it was a scam, most showed low percent trust but I found some that said it was trust worthy and went through with it. Go to https://www.obtgame.com/verified-sudden-attack-korea-account.html and purchase the account. I received mine within the day. I haven't had ANY problems since.
Next you'll receive the account via email from your obt account or paypal email. Log in to make sure it works. Be sure to change your password. They offer a guide on how to change your password. https://www.obtgame.com/blog/tutorial-change-password-verified-nexon-korea-account/
Login on the Site.
After you proceed. It will have you confirm your login information and have a verification test to make sure you are not a robot.
Now to Download
After you login you'll be redirected back to the page. What you'll want to do next is click on Game Download. Which is above where the login was at.
On the next page, scroll down a very little bit and you see 3 big buttons. The one you need to pay attention to is the middle gray one with 01 ,02, 03, 04, 05, and 06. Below that you can see the Specs needed to run this game. Click on the 01 to start the first download, then the 02, 03, 04, 05, & 06. They will each take roughly 10-30 minutes.
After it is finished downloading. Put all of them in a single folder together and run sainstall.exe
It will need Admin rights to run. After it'll pop up asking the download location. Click the left button. Then the installer will show up. Click the bottom blue button to start the installation.
After it finishes I think you can just close it, I don't recall. You'll then want to run the launcher to patch it. Open your files. Go to C:\Nexon\SuddenAttack and run ghsalncr.exe
The patcher will pop up and it will take a while the first time it runs. So give it all the time it needs.
When it is finished it will pop up a Message. When you click OK it will close and nothing else will happen.
Now you can go on the main SA site. Make sure you're logged in. When you hover over Game Start above your account info, you'll see Combat Server, Clan Server, and Survival Start. You'll want to click on Combat Server. After that, it will launch, you'll have to download the I guess hackshield things first. Then the game will launch and you'll be asked to create a Nickname(first time using)!
How to get onto a Popular Server Push exit at the top right after your game first loads.
Usually the one in the picture below is the most popular server. I've seen it reach up to 3-4k