안녕하세요! It's Koreanstudyjunkie here and this will be a quick, summarized lesson about -고!
I made lessons about 하고, (이)랑, and 와/과 here.
-고 = and
Usage: This grammar can have 3 different main usages. -고 is attached to a verb stem between two sentences to connect them. The tense of the sentence is usually expressed in the second/very last verb in the sentence.
The first usage: used when listing more than two equal facts.
이 가방이 싸고 예뻐요. → This bag is cheap and pretty.
The second usage: used when the first action and the following action happen in order. sometimes translated as “and then”. (I do this AND THEN that)
운동하고 책을 읽을 거예요. → I will exercise and then I will read a book.
컴퓨터하고 운동할 거예요. → I will use the computer and I will work out.
The third usage: used when an action or result of the first sentence stays the same while the following action happens.
지수는 새 신발을 신고 학교에 갔습니다. → Jisoo went to school in her new shoes.
할아버지는 항상 안경을 쓰고 책을 읽으십니다. → My grandfather always wears glasses and reads books.