Accusative
The accusative (or object form) refers to the person or thing after the verb e.g. I see her, I sell the CAR, we buy the ticket.
The only difficulty occurs when the noun is MASCULINE, as that changes – ich sehe DEN Baum
The NEUTER and FEMININE forms don’t change – ich sehe die Frau ich sehe das Boot HOWEVER .
Easiest way of teaching it is to say – die Frau sieht die Frau (it’s ‘die’ before and after the verb).
It is unlikely that you will ever write das Boot sieht das Boot (it’s ‘das’ before and after the verb) but you did, your grammar would be excellent.
HOWEVER der Mann sieht den Mann. (the masculine changes from der – den). It’s no big deal really but at an early age in the language we tend to forget to adjust the masculine form.
The plural form doesn’t change either. Die Elektriker sehen die Elektriker (The electricians see the electricians).
The person/thing BEFORE the noun is called the SUBJECT and the person/thing AFTER is called the object. In your German classes at SCHOOL, your teachers refer to the SUBJECT as the NOMINATIVE. This comes from ‘NOME‘ in latin = name. We learn the name of a noun as der, die, das. After that, you have to check whether the noun is before or after the verb.
You make these changes in English all the time. You don’t say “I see he” you say “I see him“. That change from he (nominative form) – him (accusative form) (or the object form). Two ways to say the same thing.
me = mich, you = dich, him = ihn, her = sie, us = uns, you (pl) = euch, you (polite) = Sie, them = sie. Surely this is easy as making a pie