Dual boot help ubuntu wibdows 10

I am trying to install Ubuntu 20.04.1 on my Dell latitude 3410. Windows 10 pro. It has an Intel i5, 8gb ram. I originally shrunk about 60gb of my C drive to make room for it and can see the allocated space that it will use in disk management. I bought a memorex 3.1 usb and used unetbootin to make a live usb. When I went to install, I had an error that it could not continue since intel RST was enabled. I followed this guide (http://triplescomputers.com/blog/uncategorized/solution-switch-windows-10-from-raidide-to-ahci-operation/) and switched from RAID to AHCI.

• Now I can get windows to boot normally but my flash drive is no longer detectable. It shows up fine in my Lenovo laptop and when I restart my Dell, it will flash for a few seconds during the load up then it stops flashing and is not found when I'm on my login screen. I tried finding it in device manager and it is not found. I thought I was finally able to continue the ubuntu installation and now I'm having this problem, please help. Thank you.