C# 5.0 .Net WindowForms application storing user specific settings in config fiel while runtime using Jetbrains Rider

IDE:JetBrains Rider 2020.3.3Build #RD-203.7148.23, built on February 17, 2021

Application Info:Target framework: net5.0-windows7.0Language version: c# 9.0

https://github.com/githubTh3o2211/simpleBackup/tree/switfUpload/SimpleBackupon branch swiftUpload

What i trying to archive ?as title mention iam trying to store some user specific data from a settings form to somewehere using .NET configurationManger or equal solution. So basically iam looking for best pratice information for doing that on a webform application

What i did before?I searched for a long itme but at the end i was landed everytime to this topic:

https://docs.microsoft.com/de-de/previous-versions/visualstudio/visual-studio-2015/ide/managing-application-settings-dotnet?view=vs-2015&redirectedfrom=MSDN

But it seems with my ide i cant use it or i dont know how.

So as you can see, iam more or less looking for a good soul to send me some hints or best pratices

Thank you for your help!