You can change the save directory in the launcher, or create a new profile with a different directory if you have other worlds you want to leave on the SSD.
In the upper right of the launcher there are three white lines that turn green when you put the cursor over them, clicking will turn on the menu row under the title.
Clicking on "Launcher Settings" gives you a list of profiles (there may of course be only one).
Clicking on a profile brings up its settings.
The Game Directory is in the middle row, if it's greyed out you need to click on the "switch" to the left of it to enable changing it.
So create a directory on your HD and go to the launcher and switch to that directory for the profile. The icons to the right let you browse your file system to find the directory you want, or you can copy and paste the directory when you create it.
Then you need to copy the files from the original directory (on the SSD) to the new directory.
(Assuming you are in the right section of the forums, if you are asking about the Win-10 edition (or some other edition of Bedrock) the answer would be different.)