Japanese Unit 4 Lesson 5

I'm hoping a lot of the grammar things I don't understand from this chapter will soon become clear. ...

onnanohito tachi wa kuru tokoro desu: The girls are approaching.
onnanohito tachi wa iku tokoro desu: The girls are going (leaving).
uma wa kuru tokoro desu: The horse is approaching.
kappuru wa iku tokoro desu: The couple is going.

kabe o nobotte imasu: Climbing the wall.
kaidan o nobotte imasu: Climbing the stairs.
kaidan o orite imasu: Coming down the stairs (no idea what orite is as of this moment).
hashigo o notobtte imasu: Climbing the ladder.

neko wa nemutte imasu: The cat is sleeping.
neko wa nemutte imasen: The cat is not sleeping.
akachan wa nemutte imasu: The baby is sleeping.
akachan wa nemutte imasen: The baby is not sleeping.

neko wa nete imasu: The cat is going to sleep. (neru = go to sleep and nemuru = sleep?)
neko wa okite imasu: The cat is awake.
achachan wa nete imasu: The baby is going to sleep.
akachan wa okite imasu: The baby is awake.

kappuru wa kuru tokoro desu: The couple is approaching.
kappuru wa iku tokoro desu: The couple is leaving.
kappuru wa kisu o shite imasu: The couple is kissing.
kappuru wa kisu o shite imasen: The couple is not kissing.

uma wa ban no naka ni haitte iru tokoro desu: The horse is entering the bus(?).
uma wa ban kara deta tokoro desu: The horse is exiting the bus.
kono otokonoko wa mizu no naka ni hairu tokoro desu: This boy is entering the water.
kono otokonohito wa mizu kara dete iru tokoro desu: This boy is exiting the water.

onnanohito wa esukareetaa de agatte imasu: The woman is going up the escalator.
onnanohito wa esukareetaa de sagatte imasu: The woman is descending the elevator.
otokonohito wa kaidan o nobotte imasu: The man is climbing the stairs.
otokonohito wa kaidan o orite imasu: The man is going down the stairs.

kono hito tachi wa esukareetaa de agatte imasu: These people are going up the escalator.
kono hito tachi wa kaidan o nobotte imasu: These people are climbing up the stairs.
kono hito tachi wa esukareetaa de sagatte imasu: These people are going down the escalator.
kono hito tachi wa kaidan o orite imasu: These people are going down the stairs.

otokonohito wa hikooki ni notte iru tokoro desu: The man is boarding the plane. (riding?)
otokonohito wa hikooki kara orite iru tokoro desu: The man is getting out of the plane.
otokonohito wa torakku kara orite iru tokoro desu: The man is getting out of the truck.
otokonohito wa torakku ni notte iru tokoro desu: The man is boarding the truck.

kappuru wa tatemono ni haitte iru tokoro desu: The couple is entering the building.
kappuru wa tatemono kara dete iru tokoro desu: The couple is exiting the building.
otokonohito wa basha ni notte iru tokoro desu: The man is boarding the coach.
otokonohito wa basha kara orite iru tokoro desu: The man is exiting the coach.


Okay...

So much ambiguity here. I don't know the real difference between "sagatte" and "orite", or why you would use "orite" instead of "dete" for some things, (maybe for climbing vs exiting?) or why you would use "deta" instead of "dete".... (horseVShuman?) or when exactly tokoro should be used. I'm very confused.... sigh.