I need help setting up Easy Cap with HDMI

I recently bought an Easy Cap so I could enter the EVO Online tournament, but my 360 is connected to my TV with HDMI. What do I need for it to work and how do I hook it up?

I’ve never used any kind of capture card and I’m not good with computers, so I’ll need it explained as if I were a 4-year-old.

Thanks in advance.