Homebrew Sram patching and changing GBAR2 version on DSi in order to save Golden Sun 2: how?

[Dexav]

Hiya, apologies if this is a silly question, but I'm a noob at all of this, and google isn't helping anymore.

In order for me to save Golden Sun 2 on GBArunner2 on DSi (via SD card), here's what Wikitemp states:

Use commit unspecified (2019/06/03) (sd save branch) arm9 version instead. Sram patching for saving is required in that build. Game runs faster with wram i-cache enabled.

I have downloaded "Commit unspecified (2019/06/03) (sd_save branch)", and that's as far as I managed to make it by myself. I have no clue how to replace the version of GBArunner2 I already have with the downloaded version, or how to perform a Sram patching. I also have no idea what a wram i-patch is or how to enable it.

Could somebody patiently walk me through the steps I need to perform to save Golden Sun 2, or point me in the direction of some tutorials? Keep in mind that I'm completely new to all of this, and I don't even understand the most basic jargon.

Thanks a lot in advance!