It sounds like you are seeking to use Swap Magic to launch PS2 ELF files... if so, just make a folder called "SWAPMAGIC" (without quotation marks) on your USB stick/pendrive and rename your PS2 ELF file as follows to launch it with Swap Magic 3.6+ disc:
SMBOOT0.ELF = (Press Up + L1 to launch if named this)
SMBOOT1.ELF = (Press Up + L2 to launch if named this)
SMBOOT2.ELF = (Press Up + R1 to launch if named this)
SMBOOT3.ELF = (Press Up + R2 to launch if named this)
So if your PS2 ELF was originally called "Demo.ELF" then you would rename it to "SMBOOT0.ELF" and trigger it via pressing Up + L1.