Guide into the most nostalgic thing in steam
• The only thing you need is to download Steam Friends Patcher[github.com]
  
  after downloading SFP (Steam Friends Patcher)
  
  1. Download 2013 Steam Library[gamebanana.com] and 2010 Steam Friends list[gamebanana.com]
  2. Open SFP and click on open file and open the friends.custom.css and the libraryrootcustom.css
  
  
  
  3. Open The 2013 Inspired Steam Library and The 2010 Inspired Steam Friends list
  
  4. Copy And Paste the Content from The 2013 Inspired Steam Library to libraryrootcustom.css and The 2010 Inspired Steam Friends list to The friends.custom.css
  
  5. Click Patch (it is unfinished btw)
  
  6. Download 2013 Steam Skin[gamebanana.com]
  7. Extract the steam2013_0be70.zip into your steam skins folder (C:\Program Files (x86)\Steam\skins)
  
  
  8. Open the Steamclient then go to Settings -> Interface -> Select the Steam 2013 skin
  
  
  9. Enjoy the nostalgic feeling :D

the additional stuff is to change the steam icon (its simple)
Requirements: any steam icon from google with .ico as the extension file
1. Right Click on steam's icon on the taskbar
2. Click on properties

3. Click on change icon
4. Choose your custom steam icon