"He wanted to learn how to swim."
Translation:Él quería aprender a nadar.
Because he could still want to learn how to swim. If the action has the possibility of still existing, use the imperfect. If you know for a fact that his wanting to learn how to swim only resides in the past and no longer exists, then you can use the preterit
Think of it as "He wanted to learn to swim." The how is not needed in either language. Apprender a = to learn how to do something.
Here is what i found about the difference between "apprender como" and "apprender a". It is worth to mention that both are grammatically correct. However in our case using "a" instead of "como" would be more approriate because "a" is used to make general statements. If the statement was about learning special way of swimming, "como" would be used. Overall it is general vs concrete(specific). Source: http://forum.wordreference.com/threads/aprender-a-v-aprender-como.1073440/
He wanted to learn like swim?
Oh, you mean cómo, of course.
I think aprender just comes with its own preposition.
Maybe he was a valley girl... he like wanted to like learn to swim like... Yes, meant cómo, of course.
you use the imperfect past tense (queria) when describing an ongoing state of mind; quiso is the preterite, and it would be used for an action that had a definite stop and start time