Learn Polish: Chcę, żebyś natychmiast poprawił tę prezentację. - I want you male to correct this presentation immediately.

When you want someone else to do something, Polish uses żeby followed by the past tense form of the verb (the l-participle). The personal ending -ś (you) attaches to żeby to make żebyś, leaving the main verb in its base 3rd-person past form poprawił.

How do we know from the Polish sentence that I am speaking to a man?

The past tense form of the verb shows the gender. Even though the 'you' ending -ś jumped over to the front to create żebyś, the main verb is still the masculine form poprawił. If you were telling a woman to do this, you would say Chcę, żebyś natychmiast poprawiła.

I hear native speakers say tą prezentację all the time. Why is it tę here?

The word prezentacja is a feminine noun, and the direct object of the sentence needs the accusative case. In strictly correct written Polish, the feminine accusative of 'this' is tę. In everyday spoken Polish, native speakers very frequently say tą (which is technically the instrumental case), but since correcting a presentation implies a professional or academic setting, the grammatically strict tę is better here.

Could I use the imperfective verb poprawiał instead of the perfective poprawił?