First, you must download these two programs if you don't have them:
Winrar[www.win-rar.com]
Slade[slade.mancubus.net]
After downloading, install them!

Now download only one of the source ports, the ones recommended are:
GZDoom[www.osnanet.de]-click version number to download.
Zandronum[zandronum.com]-click on your preferred version to download.

The last thing to download is the "Master Levels Menu". To get it, click here[www.doomworld.com] and click one of the mirrors on the right, preferably the one that's both the closest to you and supported.

Once you downloaded the two archives, cut them. Hold the" Windows Logo" key on your keyboard and press the "R" key. In the window that opens, paste this:
C:\Program Files (x86)\Steam\SteamApps\common\Master Levels of Doom.

You'll be taken to a very important folder. Paste the archives there.

Now delete everything except:

• The archives you pasted there earlier
  
• Folder named "doom2"
  
• Folder named "master"

So the only files left are:
After doing so, extract the archives to where they are.
If using the Zandronum installer, select "Portable Installation" and choose to install in the folder the installer is, better by pasting that path from earlier in this guide.
After the extraction, delete all archives. Rename the EXE file to "dosbox.exe".
Now go to the "doom2" folder and cut "DOOM2.WAD". Return to the folder you were before and paste that file, afterwards delete the "doom2" folder. Open "ZDLMENU.PK3" with Winrar and keep it open for the next step.

Go to the "master" folder, then go to the "wads". Delete all the TXT files. Make a copy of the "TEETH.WAD" file and name it "TEETH2.WAD". Now open SLADE3. Drag and drop "TEETH.WAD" in there. Select the selected files on the image:
Press "Delete" on your keyboard, then hold "Ctrl" and press "S". Click on the "X" next to "TEETH.WAD".
After that, drag and drop "TEETH2.WAD" onto the program. Select the selected files on the image:
Press "Delete" on your keyboard, then hold "Ctrl" and press "S".
Close SLADE3. Delete the BAK files SLADE3 has made. You still have the "ZDMLMENU.PK3" archive open. Go to the "maps" folder in it. Now drag and drop the WAD files to that folder, just like in the picture.
Save and close. You may now just delete the "master" folder if you want.

Open Master Levels' properties in your library, the click "Launching parameters". In the window that opens, paste this:
Save and close. Once you boot the game through Steam, select Doom 2 and click "Don't show this again". Now you'll have a nice working level select, better loading times, improved audiovisual presenation, controls customizable to whatever you wish and multiplayer depending on what source port you are using.



That's all, wish you a good day! :-)