Optimal use of both HDD and m.2 SSD

Hey there first post + new to linux. I am just jumping off from windows and I am kind of taking a thrown into a deep end approach. I am trying to get set up and getting my rig to be optimally used by Ubuntu.

I am having a bit of trouble trying to get good use out of having a HDD being used for general file storage and m.2 SSD at the same time. Essentally I just want my /home on the HDD, HDD encrypted, and to decrypt and mount at startup.

Now I am used to on windows just changing the file location in explorer, but not so sure how to make it so that files get saved to the HDD in ubuntu. I found a tutorial on askubuntu and it seems like the right direction.

I went though with this but got stopped at the end when the partition i made for the storage wouldn’t mount after restarting (even manually), said the partition was busy. I think this could be because I made 2 partitions one for Linux and one for the reinstall of windows later on. I reinstalled Ubuntu as this post was made so I am technically not stuck there anymore but dont want to get stuck there again.

If anyone has advice to get this working or maybe a different method. Even general advice on how to make sure I have Ubuntu optimally using my machine’s hardware will be appreciated as well.

What mount point did you choose for your HDD?

Did you choose “home directory encryption” or “full disk encryption” when you installed?

Is your current /home partition on your SSD? Sounds that way from your post.