Studying law question

I am trying to study law to better understand it and am confused and wondering about certain cross country/state law conditions. To better ask, I'll provide 2 states to be used as an example. Let's say Florida and Nebraska. Since Florida has a Age of Consent Law of 18 years old, I'm seeing that Nebraska has it for 16 years old in some places and 17 years old in other places. I'm not sure which one so that's the first question so I can better understand this conditional law thing. Let's say 1 person lives in Nebraska being 17 years old and the other in Florida being 21 years old. "Florida statutory rape law is violated when a person has consensual sexual intercourse with an individual under Age 18. Close in age exemptions exist, allowing minors aged 16 or 17 to engage in sexual intercourse with a partner no older than age 23." With this being stated, Does this only apply to actual sex or any sexual activities? Same question applies for if they participate in sexual actions only and not actual sex Online instead of being in 1 state. For the next question, let's say that they participate in sexual actions Online. It does say "Close in age exemptions exist, allowing minors aged 16 or 17 to engage in sexual intercourse with a partner no older than age 23." but does this apply for cross state being specified above and being Online? Is it legal or illegal for these two ages to do anything stated above? Same questions would apply if the ages were 18 and 21. Is it legal or illegal for these two ages to do anything stated above?