c# read files like this

I wanna open some files of a game client (my server) to edit these values placed in the file and save it again after finished editing. Since there are fewer good public tools outta there to edit this, I need to write one. I'm not new to c# but I dunno which keyword I'm searching to inform myself about it.

The file looks like:

`https://pastebin.com/ePhwTNSi`

How do I get started on reading this?