1. Partition HDD, create Pop_OS live Linux usb (or desired Linux distribution, just remember to include Nvidia/AMD graphics driver).
2. Install OS, with separate /boot partition than Windows.
3. Return to Windows (can do this as step 1 actually) and install rEFInd boot loader on Windows EFI partition and replace bootx64.efi or whichever default boot file for your BIOS with rEFInd.efi.
REFInd should automatically locate both installs next time you boot.