I have some knowledge of how to install and dual boot Windows-Ubuntu. In the past I played with this and make a lot of mistakes. I use an old windows computer (Dell Vostro 1540). It is almost 10 years old but still working great. I upgraded it with 8 GB RAM and 250 GB SSD.
One thing I learned the hard way was to backup my computer before doing this. In the past I destroyed my Windows installation. Because I don’t have too many documents in my computer this was easy. I just installed MEGA and uploaded everything there.
The Odin Project does give you a good overview of how to install Ubuntu or Xubuntu. I choose to go with the VirtualBox route but I painfully discover that my old, almost 10 years computer is to old to run VirtualBox without lagging. So Instead I went to dual boot Xubuntu alongside windows 10. I have never used Xubuntu before and I wanted to give it a try, so idecided not to install Ubuntu.
I used this guide: https://www.tecmint.com/install-ubuntu-alongside-with-windows-dual-boot/ and the one in The Odin Project, and because I wanted to refresh my mind (I’m very visual) I watched this two videos: