My question is about the novel of In the Fog of the Season's End by Alex La Guma. So, in what ways do form and content conflict in La Guma’s novel? And how might we understand these conflicts, and can they be resolved? I need a reference, too.

In order to answer your question, it is important to distinguish form and content. The content of the novel would be its plot line, characters, and themes. The form of the novel would be the organization, style, and pretense of the writing itself.
In Alex La Guma’s In the Fog of the Seasons’ End, there are several ways in which the form and content conflict, meaning they do not seem to coincide or work together effectively.
Perhaps the most glaring of these is how Beukes, the novel’s protagonist, seems unassailed by the horror and gravity of his journey. As a dedicated member of the anti-apartheid movement, Beukes bears witness to squalid living conditions, unabashed discrimination, and even violent retaliation from those who oppose his cause. A reader might expect that La Guma would depict these incidents with a similar degree of horror and violence. Despite this, the tone in which these incidents are described can be labeled as placid. The juxtaposition of the turmoil of the events and the calmness of the tone is just one way in which the form and content could be said to be in conflict.
Another conflict between the form and content could be that La Guma uses literary fiction to deliver a political commentary about Marxist philosophy’s superiority over the authoritarian capitalism as represented by the white ruling class of South Africa. Several literary critics have pointed out that La Guma writes a thinly-veiled propaganda piece in support of the communist revolution instead of a work in which his artistic vision is paramount. In this way, one could argue that La Guma would have been more successful in communicating his message in a work of nonfiction, since he was himself an anti-apartheid activist like Beukes.
I think you might say that understanding these conflicts is open to individual interpretation. As far as the contrast between tone and content, one could argue that La Guma deliberately chooses to use a disparate tone in order to underscore both the brutality of existence under apartheid and the resistance fighters’ resolute dedication to their cause in the face of such horrors.
As far as the conflict between the fiction genre and the message of the work, one could argue that La Guma uses literary narrative to make an abstract message more real and relatable to his audience. If his purpose is to motivate South Africans to demand change, then perhaps he believed an idealized narrative was the best vehicle for achieving said purpose.
In these respects, I would say that it is easy to reconcile these seeming conflicts when considering La Guma’s underlying motive for composing the text.