HOW DO I PRINT THE SHEETS?!

I keep seeing things that are not clear answers or they have jargon that does not make sense all referencing one confusing Roll20 post. Basically can I or can't I print character sheets? We have been hosting D&D campaigns for the teens at the library where I work. Often times we make the characters for them and they just play. It would be SUPER GREAT to be able to give them a printed sheet ahead of time so they can learn their characters and be ready to play day of. 

You can pop sheets out in their own window and try printing from there. You would need to print out each applicable tab.  You would also need to have an collapsible content expanded that you want to have visible in print. However, sheets are written to display on Roll20, so may not print well because presentation on paper isn't the format the sheets are written to fill.  You will have to try it and see.  If I understand correctly, there have been changes to the character sheet framework that would allow this to work more reliably, but it requires sheet authors to code in a printer friendly format to apply when attempting to print out a sheet. I know there was some sort of browser extension that would help print sheets at one point, but I don't know if it still exists/works because I have never used it.

As Kraynic said, use the setting to popout your character sheets from the main Roll20 window and then print from there.  Use your browser's preview function because you may need to manually set a reduction % to fit to the page width.  Roll20 is working on making sheets easily printable but that's still a bit away.

Another popular option is to use Character builder in DnD Beyond, you can print nice character sheets from there.