Creating working HD image for Hatari (or Steem) is 2 step process. First you need to make one empty file of desired size.
Max 2GB in case of Hatari and IDE, or 1GB in case of ACSI emulation. For instance with HxD editor (free).
Second step is partitoning and installing autoboot driver - with some proper tool. As freeware solution you may use AHDI driver. There are some others, but are not free (Hddriver) or are too old. Get AHDI here: http://ppera.07x.net/atari/GamexUsage.html
(DL AHDI 6.04).
After it you may use under Hatari, with autoboot or even with loading driver from virtual floppy (ST image files).
Another way is to get prepared image file what is already partitioned and has installed autoboot driver.
May ask for it here: http://ppera.07x.net/forum/
Btw. Hddriver is not recommended for Hatari - because of some emulation issues with.