I found this confusing too. I know we are all “perfectly fluent” in grammar speak here, but ‘main verb’ wasn’t initially clear to me either, and became less so when working the examples. In some examples, the verb after après que is underlined, in others it is the main verb. It would be good to highlight both distinctively so it is easier to identify both.

Running through the examples as I understand them (maybe I don’t) :

For main verb passé composé

1. Après que vous avez visité la ville, vous êtes allés boire un verre.

Passé composé/ passé composé  -main verb

2. Après que j'ai vu ce film, j'étais bouleversé.

Passé composé/imparfait followed by adjective - main verb (bouleverser conjugates with avoir so this is not plus-que parfait, that would require “avais été bouleversé”)

3. Il a laissé sa voiture au garage après qu'elle était allée à la banque.

Passé composé - main verb/plus-que parfait

For main verb present indicatif

4. Après qu’ils sont arrivés, ils vont saluer ma mère.

Passé composé / futur proche - main verb (vont is present tense, but the construct is aller-infinitive, and vont has an auxiliary role here - not exactly present indicatif, as mentioned in the commentary).

5. Tout le monde part après qu'elle sonne la cloche.

Present - main verb/present

6. Je me lave après que tu te lèves.

Present - main verb/present

Examples 2 and 4 don’t fit fully with the explanations given. 

It would be good to clarify further - as I think all the examples are correct, the lesson needs a bit of expansion to cover the current “gaps”. The main introduction refers to mode indicatif, but the commentaries on the sections specifically mention only present indicatif/passé composé and plus-que parfait. 

Hi Marteen/Vicki,

#1. Both verbs in passe compose. Apres verb 'êtes allés' happened just when he ended his tour.

#2. "Après que j'ai vu ce film, j'étais bouleversé" the main verb is 'ai vu' (passe compose) and the 'apres que' verb is supposed to be in the plus que parfait... because the 'overwhelming' is both a state and presumedly lasted well after the seeing. Looks to me that the verb is missing the reflective pronoun 'me'! It is like endormir vs s'endormir (put qqun to bed vs put yourself to bed)Former conjugated with avoir; latter with être. Overwhelm someone VS be overwhelmed.

#3. Difficult sentence for timing ! But the 'apres verb' is  'était allée' and the subject of that verb is 'she'. The main verb/subject is 'il a laissé'!  'était allée' is in the plus que parfait because there is a long time span between the events. Maybe he had to drive across town to the garage.

#4. Main verb is present indicative. The 'Apres verb', sont arrivés, is in the passe coompose and not the present tense because the HABITUEL action of arriving of course happens (before) and  then the go and say hello. 

#5/#6 simultaneous almost.. bell goes everyone leaves/you get up/i wash.... main verbs in present tense so 'apres verb' likewise.

Hope I am right...especially looking for clarification with bouleverser.

I am confused... we are using le passé composé to describe a habitual action? (Après qu'ils sont arrivés...) Shouldn't it be le présent indicatif or l'imparfait?

Jameson and Vicki

Late to see the comments, but just to note that bouleverser is not reflexive - that clause is not plus-que parfait with a reflexive pronoun missing.

It is simply imparfait - adjective (past participle). 

As translated it is describing a state of being. You could use passive voice to describe being overwhelmed by something, (étais bouleversé par….), but that is not the way it is presented or translated here.

Après qu'ils arrivent, ils vont saluer ma mère?

Après qu'ils sont arrivés, ils allaient saluer ma mère.

I agree that this sentence is slightly different than the qualifying

examples. All of the examples sound more like a conditional than

an imparfait. e.g. "I would have done something if it had been under better circumstances."

In English, this case of the futur proche dans le passé doesn't sound like a

futur proche tense. It sounds more like a conditional not otherwise specified.

In the positive construction, "The pilot sent a message

to central command that he was going to land earlier than expected," the

verb tense sounds like a definite going to event. 

I found this lesson helpful:

Aller can also be used in the imperfect to say "was going to do" something. This construction is known as le futur proche dans le passé or le futur périphrastique au passé.*

Par exemple…

 In English, you can say "I am going to" or "I was going to” and it’s a complete sentence. But French needs more: you have to include an infinitive.

Après qu'ils arrivent, ils vont saluer ma mère?

Après qu'ils sont arrivés, ils allaient saluer ma mère.

I agree that this sentence is slightly different than the qualifying

examples. All of the examples sound more like a conditional than

an imparfait. e.g. "I would have done something if it had been under better circumstances."

In English, this case of the futur proche dans le passé doesn't sound like a

futur proche tense. It sounds more like a conditional not otherwise specified.

In the positive construction, "The pilot sent a message

to central command that he was going to land earlier than expected," the

verb tense sounds like a definite going to event. 

I found this lesson helpful:

Aller can also be used in the imperfect to say "was going to do" something. This construction is known as le futur proche dans le passé or le futur périphrastique au passé.*

Par exemple…

 In English, you can say "I am going to" or "I was going to” and it’s a complete sentence. But French needs more: you have to include an infinitive.