NEED to install Halo Wars 2 on HDD, HELP!

Hi all!

I own Halo Wars 2 (and a bunch of the DLC content) on the Microsoft Store, trying to reinstall as I just got a new internal SSD and moved my Windows 10 to it.
However, my SSD is supposed to be the boot drive. I want all content to stay over on the old HDD as the SSD has very little free space.
The Microsoft Store recognizes my HDD and gives me the option to install to it, HOWEVER clicking on the HDD in the drop-down install menu does nothing. Nothing happens when I click the button.

I’m trying a different solution from my end.

I managed to clear just enough space on my SSD to install the game. Once it’s installed, I can move it to my HDD.
However, now, whenever I try to use the Store app to install to the SSD, I get: “Try again later” as an error message.
I know bugs happen in almost any software environment, but for such a basic feature as the Store to be so bugged and uncooperative, it’s very frustrating. I just want to reinstall a game that I own so that I can play it.

I took a different approach: I managed to clear enough space on my SSD to install Halo Wars 2. My intention was to use the Control Panel (Apps and Features) to move the program to the HDD.

But now I am getting error code: 0x80070005 when I try to move the program. Apparently this is a permissions error. I don’t know what to do about this; ever since installing my new SSD, my system has been treating my old HDD like somebody else’s drive. I’ve gone into the Security settings and changed everything I could find to give me effective permissions, but I’m still getting this problem.

In the end, I did decide to keep HW2 on my SSD. Now I have only about 15 GB of free space, but I may just have to live with that. I have to admit, the lightning fast load times are a real treat.