Link for recent How-To for dual boot on a single SSD

I just bought a LG laptop with a 2 TB SSD and would like to dual boot it.

My last adventure in dual booting did not go well and I want to make sure I don't repeat any of those mistakes. There were issues with Secure Boot and I ended up making that computer a dedicated KDE machine.

I am looking for a How-To dual boot a laptop with both Win11 and KDE on a single SSD.

Thanks.