which firmware link for Repetier with Prusa i3?

hello all!
I'm Rob (50+) not so good (somewhat uncertain) with software.
I have a Prusa i3 and controlled the printer with a PC. (that worked reasonably!)
I have gotten a laptop (with windows) from my son and want to print wiht Repetier host.
I have Arduino IDE already on the laptop and Repetier host also from here:
[www.repetier.com]
but now I need firmware (Marlin?) also to set up the laptop!
when I click the link for Firmware I arrive at Github:
[github.com]
my question is:
which link is the link to the good software?
I mean for my Prusa i3.

I hope that the written NL/English is good translated (Google translate)
I myself am from the Netherlands and the combination of English and software to be honest i am not really good at
(I manage happily!!! by asking many questions on forums!!!) ;-)
I now hope again that someone can help me?

here a movie that I am very pleased that the printer and the print were successful:
[www.youtube.com]

Kind regards from location Rotterdam (NL)
Rob.

it's still here!
happy with some help from a friend I succeeded!
The printer works, I just need to adjust.

everyone the warm greetings from here!
Rob.