The direct object marker
אֵת (often אֶת) flags a definite direct object. It has no English word of its own.
When it appears
Typically before a definite object: article, name, or suffix. Genesis 1:1 uses it twice. Indefinite objects usually go unmarked. It is not the preposition "with," though the same consonants can be that preposition in other verses.
(object) the heavens
Gen 1:1(object) the earth
Gen 1:1With suffixes
אֹתוֹ him, אֹתָהּ her, אֹתָם them, אֹתִי me. These forms are extremely common and worth memorizing as a set.
him (object)
her (object)
them (object)
me (object)
"With"
אֵת / אֶת plus a noun can also mean "with." Suffixes then look like אִתּוֹ. Dictionaries list two lemmas; context (object of a transitive verb versus accompaniment) decides.
with him
Read next
The definite article
הַ plus a following dagesh is the basic "the." Vowels under ה change before gutturals.
Genesis 1 word by word
The opening of the Torah is the usual first connected text: a few roots, heavy use of wayyiqtol, and the object marker.
Pronominal suffixes
Person is glued to nouns, prepositions, and some particles: my, your, his, our.