To create a bootable USB installer for AlmaLinux 8. Follow the steps below:
Step 1 : Download the AlmaLinux 8 ISO file from the official website: https://almalinux.org/get-almalinux/

Step 2 : Download Rufus from the official website: https://rufus.ie

Step 3 : Insert your USB flash drive into the computer. Make sure the USB has sufficient capacity, and note that all existing data will be erased.
Step 4 : Open the Rufus application.

Step 5 : Configure Rufus using the following sub-steps:
- Select the USB flash drive in the Device field
- Click Select and choose the AlmaLinux 8 ISO file
- Choose the appropriate Partition scheme (MBR or GPT)
- Leave File system and other options at their default values

Step 6 : Click the Start button to begin creating the bootable USB.
Step 7 : When prompted, choose Write in ISO Image mode (Recommended) and click OK.

Step 8 : If Rufus asks to download required files such as a newer Syslinux version, select Yes.

Step 9 : Confirm the USB formatting warning by clicking OK.

Step 10 : Wait until Rufus completes the process.

Step 11 : After completion, safely eject the USB flash drive.

Congratulations, you have successfully created a bootable USB installer for AlmaLinux 8 and can now use it to install the operating system.