Might be that you didn't install intel-ucode or amd-ucode.

Did you use btrfs ? Did you encrypt with luks ? Because if so, you have to add the hooks to /etc/mkinitcpio.conf.

If you didn't encrypt your drive or use btrfs, have you installed GRUB beforehands ? Because that screen might be from your old GRUB. If so, you need to install GRUB.

If so, reboot to your liveISO. Mount /, mount /boot then do :

arch-chroot

grub-mkconfig -o /boot/grub/grub.cfg

grub-install --target=x86_64-efi --efi-directory=esp --bootloader-id=GRUB

If that does not make sense or you need help figuring out, just reply to the comment. Arch is hard to install the first time. It often takes several tries to get it right. It becomes easy the second time round.