I probably sound like an idiot but I just recently bought my SP-404sx and I can't figure out how to export my patterns/beats onto my computer. Any help would be appreciated.

For sequencer MIDI data check the editor on the "Hacking the 404(SX)" topic.

For actual audio it's just a matter of having a card reader that takes SD cards (most computers have these built-in). Check the manual for that.

Quick way: recording the SP-404(SX)'s line outs through the soundcard/an audio interface.