First you need to understand the simple cases (one or two verbs) before trying to get to the more complicated ones.
If there is only one verb, its position depends on whether the sentence is a yes/no-question (verb first), a statement (verb second) or a subordinate clause (verb last [usually]):
(1) Erkennt er das? (Verb first)
(2) Er erkennt das. (Verb second)
(3) Ich weiß, dass er das erkennt. (Verb last)
When the verb consists there is a finite modal verb and an infinite verb, in the cases (1) and (2) we get a sentence bracket: The finite modal verb is first or second, and the infinite verb goes to the end of the sentence. In case (3) the finite modal verb is at the end of the sentence, and the infinite verb goes right before it:
(1) Muss er das erkennen?
(2) Er muss das erkennen.
(3) Ich weiß, dass er dass erkennen muss.
Now let's add a third infinite verb:
(1) Muss er das erkennen können?
(2) Er muss das erkennen können.
(3) Ich weiß, dass er das erkennen können muss.
Let's take a closer look at these sentences
The logical dependency of the verbs is: müssen -> können -> erkennen.
That's the order you use in an English sentence: He must be able to recognize this.
We can see that the first verb stays at its position (first for the question, second for the statement, last for the subordinate clause)
The second verb also keeps the same position the second verb would have if there where only two verbs: Last in cases (1) and (2) when there is a sentence bracket, second-last in case (3) when the (logically) first verb is last.
The (logically) third verb now is immediately before the second verb, in all three cases.