~고 connective verb has the same meaning as 'and' in English.
Scenarios where you can use 고
1. To state down 2 or more facts
2. To state down different events that are happening at the same time
3. To state down events happening in sequence
4. To state down preceding clause happened and continued into the next clause
5. Contents of the preceding clause is the basis or reason for the event that happened at the second clause.
Example sentences corresponding to the scenarios above stated in sequence
1. 하늘은 파란색이고 나무는 갈색이에요.
The sky is blue and the tree is brown.
2. 저는 학교에 가고 여동생은 잘 거에요.
I am going to school and my sister is going to sleep.
3. 저는 책을 읽고 샤워했어요.
I read a book and showered.
4. 저는 새 옷을 입고 회의했어요.
I wore the new clothes and had a meeting.
5. 저는 친구를 믿고 돈을 빌려요.
I believe my friend and lent (him/her) the money.