How do I select all of one color and make it completely transparent?

Looks like you've got a bunch of overlapping items, so easiest way to have everything as a completely seperate items and remove all groups, compound paths and clipping masks is:-

Save AS, just so your original isn't lost, this is destructive...

Select all, then in Pathfinder, click on merge, then click on trim.

Select the black and modify as required (transparency, opacity, color etc)

transparent as in you dont want it to be black? if so, you already seem to have selected, go to the swatches and on the color choose none,

or do you want the black to transparent but still stay as black? if so go to the opacity panel and change the opacity from 100 to whatever you want.

hope this helps.

thanks

jonahtan