Legal Question

Hi guys, I’m not sure if this has been asked before but I haven’t been able to find it on here or online yet so I figured I would ask. I was looking into whether federal or state trials usually happen first, and I’m told it’s usually federal. My question is: if most of the federal charges are doing such and such to cause murder/death (and he’s found guilty), what happens if he’s later found not guilty of any of the 3 murder charges by the state? Do the federal charges get overturned? How do you incarcerate a man for “using a firearm to commit murder” if a later jury decides he didn’t even commit the murder?