I'm not sure why you'd want to run YSMenu considering that the Bliss menu does everything YSMenu does and then some.
But if you really want to run YSMenu:[*]Download the latest version of YSMenu. Unzip the archive to your hard drive on your PC.[*]Create a folder on your microSD card named "YSMenu".[*]Place a copy of the official (not Bliss) "akmenu4.nds" into the folder you unzipped on your PC hard drive. Run "akextract.exe" to create a new file named "akloader.nds". Place a copy of "akloader.nds" into the "YSMenu" folder on your microSD card.[*]Place a copy of "YSMenu.nds" on the root of your microSD card.[*]If you want to keep the official or Bliss menu as the default menu (recommended), skip to the next step. If you want YSMenu to be the default menu, rename the old "akmenu4.nds" that is on your microSD card to something like "AK2Menu.nds" and rename "YSMenu.nds" on your microSD card to "akmenu4.nds".[*]Place the skin files "YSMenu1.bmp" and "YSMenu2.bmp" into the "YSMenu" folder on your microSD card.[*]Edit the "YSMenu.ini" file that is on your PC. Place a semi-colon in front of the line that says "LITERALS=LITERALS_JPN". Remove the semi-colon from the line that says "LITERALS=LITERALS_ENG". Also, edit the line that begins with "EXT_SAV" so that it says "EXT_SAV=.nds.sav". Save your changes to "YSMenu.ini" and place a copy into the "YSMenu" folder on your microSD card.You should now have YSMenu installed, and you can switch back and forth between the two menus by simply running the ".nds" file for the menu you want to go to.
-Bri