"you alone are cursed." The word "curse" is first in Hebrew in order to emphasize the contrast between God's blessing on the animals and this curse on the serpent. This is a "curse formula," or the way that curses were expressed. By saying this curse, God made it happen.
"You will move along the ground on your stomach." The words "it is upon your stomach" comes first to emphasize the contrast between the way other animals would move along using their legs and the way the serpent would slither along on its stomach. This is also part of the curse formula.
"you will eat dust." The words "it is dust" comes first to emphasize the contrast between the plants above the ground that other animals would eat and the dirty food on the ground that the serpent would eat. This is part of the curse formula.
The word "seed" refers to what a man puts into a woman to cause a baby to grow inside the woman. Like the word "offspring," it can refer to more than one person. Try to find a word that is singular but can refer to more than one person.
The words "he" and "his" refer to the woman's descendant. If "seed" was translated as plural, this can be translated as "they will bruise ... their heel"; in this case, consider inserting footnotes to say that the "they" and "their" are used to translate a singular pronoun. (See: [[rc://en/ta/man/translate/figs-pronouns]])