I thought I could simply install linux on my partitions and my computer would be able to select between linux and windows.
i selected my partitions and installed to the boot, root and home partitions.
Your wording here concerns me, but it's easy for a newbie to not be quite clear with terms. You never said you "created partitions"... only that you selected them during your install. You might be okay if you saw (and chose) a selection similar to "install alongside Windows." But I wonder if you may have installed Pop_OS into your existing Windows partitions... erasing Windows in the process.
@gvisoc may have been thinking the same thing... trying to get you to see if Windows Boot Manager was listed in BIOS, and if it would boot.
I've not used Pop_OS before, but I've learned this about it... it uses systemd-boot for a bootloader instead of GRUB. You may need someone familiar with systemd-boot, so be patient for other helpers to find this thread. I think most of us here only use the GRUB bootloader, so our "usual solutions" won't help you if this is the problem.
I doubt that Pop_OS has taken total control of your computer. You should still be able to get to BIOS or your Boot Menu to try loading (and installing) another Linux distro... keep trying. Read your manual, as
@brickwizard suggests. But if you aren't careful about your partitioning, you could end up with both a new distro and Pop_OS... and maybe Windows too, if it's still there.
If you can get into your BIOS settings (also called UEFI settings)... there may be an option there to do a Windows Recovery. If so, you may can restore your computer to the way it was when you got it from Best Buy (if you want to keep Windows). Or you may can get Best Buy to help you, but it may cost you some cash. The Recovery may delete your Pop_OS.
Sorry you've had so much trouble, but the learning experience is valuable too.