Handbook:AMD64/Blocks/Kernel

Architecture specific kernel configuration
Make sure to select IA32 Emulation if 32-bit programs should be supported (multilib). Gentoo will install a multilib system (mixed 32-bit/64-bit computing) by default, so unless a profile is used, this option is required.

Enable GPT partition label support if that was used previously when partitioning the disk:

Enable EFI stub support and EFI variables in the Linux kernel if UEFI is used to boot the system:

Compiling and installing
With the configuration now done, it is time to compile and install the kernel. Exit the configuration and start the compilation process:

When the kernel has finished compiling, copy the kernel image to. This is handled by the command:

This will copy the kernel image into together with the  file and the kernel configuration file.