Welcome Mehitabel! I'm afraid I don't see any ሐበሻ or other Amharic-speakers here... hopefully we'll have some in the future, this will make learning the language easier
Regarding pronunciation, you're probably confused not only b/c of IPA but also b/c of Amharic having lost some sounds from Ge'ez, resulting in different letters often being pronounced identically. So:
ሀ, ሐ, ኀ - h (maybe more like German ch, Greek χ, I'm not sure)
ሠ, ሰ - s
ጸ, ፀ - ts
You might want to check out this
page, it shows the sounds for Amharic, Ge'ez and many many other writing systems.