SD Cards and booting them as a live OS do not always mix well. Most BIOS so not support that, and the laptops I had that said they did, I only had on netbook that actually worked when booting off a SD Card, whereas the others did not. If you cannot find a boot option for your SD Card then your BIOS does not support it.
You might want to try a USB Stick. Then learn your BIOS boot order and hot keys to pres to get it to select a USB Port and not a SD Card. If you mis spoke and actually meant to say Stick. well then... back to above post.