(Original guide by MainMemory)
Ever since I set up the (now defunct) Bug reporting system for SonLVL, most of the "bugs" have been a simple case of people not understanding how SonLVL is supposed to be set up. So, this guide is here to show you exactly how to set up SonLVL.
To start with, you will need two things: a disassembly and SonLVL's updater.
Download a disassembly for the game you want to edit, and the updater, extract both to separate folders where you can easily find them. If you are not using one of the Git disassemblies, you should copy an unedited copy of the game into the disassembly and run split.bat.
For this guide, I will be using the "Sonic 1 (Split and Text by Hivebrain) (ASM68K)" disassembly, AKA the Sonic 1 2005 disassembly.
Go to the folder that you extracted the SonLVL updater to, and run SonLVL Updater.exe. You will be presented with a list of components that can be downloaded. You may select all of them, or only SonLVL and the INI files for your disassembly:
Click "Download Selected + Exit". A download progress window will open, then the program will exit when it finishes.
You should see several new things in the updater folder, including SonLVL.exe and a folder with INI files for your disassembly:
In another window, open the folder with your disassembly, which should contain at least one asm file and build.bat:
Go back to the updater folder window, right click on the INI file folder, and click "Copy" from the menu:
In the disassembly folder, right click on a file or empty space (not a folder) and click "Paste" in the menu:
A copy of the INI file folder will appear in the window:
In the updater folder, run SonLVL.exe. It should look like this:
Click on the File menu, then "Open...". Navigate to the disassembly folder, then the INI folder you pasted into it, and select an INI file that does not start with obj:
Now go to the "Change Level..." item under File, and a list of levels should appear:
After you select one, it will begin loading, then you will be able to move the camera around the level and edit it (see readme.txt for details):
After some editing, go to File, and click Save:
If you have not yet, you should now click on the "Setup Emulator..." item in the File menu, and select your favorite emulator:
Then, you can use the "Build and Run..." option in the File menu (if it is grayed out, you will have to run build.bat and start the built ROM manually):
Congratulations, you have used SonLVL to edit a Sonic game!