하다 has no meaning of its own — it is a switch

Where the picture shows up in 하다

1. 1

   a name becomes work

   저 지금 설거지해요.

   jeo ji-geum seol-geo-ji-hae-yo

   I'm doing the dishes right now.

2. 2

   the price it runs at

   이거 얼마 해요?

   i-geo eol-ma hae-yo

   How much is this?

3. 3

   switched into that state

   머리를 짧게 했어요.

   meo-ri-reul jjal-kke hae-sseo-yo

   I got my hair cut short.

4. 4

   switch this one on

   저는 냉면으로 할게요.

   jeo-neun naeng-myeo-neu-ro hal-kke-yo

   I'll go with the cold noodles.

   Ordering takes -(으)로 하다. Saying 냉면을 해요 would mean you cook the dish yourself.

5. 5

   the switch inside you

   내일부터 운동하기로 했어요.

   nae-il-bu-teo un-dong-ha-gi-ro hae-sseo-yo

   I've decided to start working out tomorrow.

   -기로 하다 is a decision you reach yourself, not an order someone gave you.