What do you use in premier to change exposure? Is Luma the same thing? I can't figure out why I can't find something so simple.

Because changing the exposure requires knowledge of the encoding curve. You can guess for many camera that is it is around 2.2 gamma. So and exposure change you have to remove the encoding curve, apply a linear gain (exposure) then restore the curve.

Just type "exposure" into the Premiere help box and you will find dozens of articles on how to do this. Generally, it's Levels in the Effects Panel, or Shadows and Highlights.

Effects > Adjust > Levels or Shadow/Highlight.

You can also go to Color Correction and choose Brightness & Contrast.