USB Installation with two particions (Kali Linux - FAT32 and persistence - ext4)

Hello, I want to install Kali Linux on my computer by using my 8GB flash drive with two partitions, as it was displayed in Kali Linux Documents.

At least 3GB for the ISO contents of Kali in a FAT32 partition, and the rest for persistence in a ext4 partition.

And I have read that I can only proceed with the persistence ext4 partition only when Kali Linux boot works.

I rebooted my laptop and selected in the boot menu to boot the content of USB drive, but I only get a flashing underscore in the upper left corner of the screen.

Any sugestions?

Thank you.