저기 literally means "there", you can use it to refer a place you're looking at or pointing to. 저기 앉으세요. Sit there. 저기 내려놓으세요. Put it down there. You could use it to get attention at a restaurant or on a street, but in this case you should use 저기요. 저기요, 서울역으로 가려면 어디로 가야 돼요? Excuse me, what's the best way to get to 서울역? 저기요, 뭐 떨어뜨리셨는데요. Excuse me, you dropped something. In spoken Korean, it could be used without any specific meaning. 있잖아... 너 내일 시간 있어? Well... Do you have time tomorrow? 저기 있잖아... 너 내일 시간 있어? 저기 뭐야, 너 내일 시간 있어? Well, do you have time tomorrow? (저기 뭐야 is very colloquial Korean, and it should be spoken in a non-rising tone.)

Hailey I mean. Gosh, my eyes aren't doing so well today.

I mistakenly thought 여기 was connected to 저기 so thank you Halley for helping me realise that!