Difference between Array and Multiple in server action

Hi,
For a server action API, I know I can declare, in its Input section, variables that I will pass as parameters to it, so those variables can be referenced in the server action steps.

I’m trying to understand the following:

1. What are the differences between a parameter declared as a “Variable” with the “Multiple” box ticked and another declared as an “Array” ?
2. What would be the syntax in the server action to address items in each of those aggregate parameters?
3. What would be the syntax in the client side to assemble those parameters so they are passed to the server action by a server connect?
4. Again in the server side, when creating an Input parameter, irrespective of the type selected (Variable, Array, and Object), I can configure something called “Linked Field”. What is it for and how is that used?

Any info on the above (or a pointer to Wappler documents where I can read about all this) would be appreciated. I searched for this info but could not find much.

Many thanks in advance,

Alex