I am having this new Function generator - AFG3000C

I am having difficulty in understanding certain terms related to this FG.

I have tried online searches, but I couldn't get what I was looking for. Being a newbie, I request you all to help me understand my queries in simple terms.
Could you please explain my queries below :

1. In this FG, we have to option OUTPUT LOAD as 50Ohms, Load and High Z. What does each mean? And where to use each one? I guess, it is related to the transmission line characteristic impedance. But where should we use the LOAD option, 50Ohms and the High Z option
2. Can we set the impedance using the FG according to our needs?
3. FG only provides Output voltage right? Can someone impress voltage on the FG channels? If so, how and how to check how much voltage can the FG withstand? How can a voltage be given as an Input to the FG output channels which are given Output only?
4. And what about the current parameter on how much current the FG can handle?

Please help me.

 

"Function & Arbitrary Waveform Generator Guidebook"
(All about FG)

Added:
AFG3000 Series Arbitrary/Function Generators Quick Start User Manual

AFG3000 Series Arbitrary Function Generators Programmer Manual

 

A situation may arise take for example an oscilloscope may have a High-Z input in order to accurately view a high impedance circuit's output without affecting the circuit. In such a case; a 50 Ohm scope probe could have an altering effect on such a circuit. Choosing high impedance the circuit's output can be seen unmolested. Same with FG . You can use the High impedance mode according to your method of isolating the FG from the circuit.

I believe your other questions are about taking care and protecting your FG.

 

You say 500 Ohms. Check it, most probably it is 50 Ohms.