Install Ubuntu20.04 in Dell(ALIENWARE M17 2020):

I want to install ubuntu 20.04 on my laptop

I follow the steps on the official Tutorials: https://ubuntu.com/tutorials/create-a-usb-stick-on-windows#1-overview

Especially, in my first try, I changed the SATA from RAID to AHCI and disable Secure Boot

But, when I boot my computer with the usb, and select ubuntu through the grub loader, the screen appeared as follows

first try

Then, I follow the steps in the link: USB installer: “ Initramfs unpacking failed: Decoding failed”. Unfortunately, I could not find the BitLocker in my Dell, but I disable the Firware TPM in BIOS. Lastly, when I try install Ubuntu, the screen appeared as follows:
second try