Conflict must be strong enough to drive the plot.
Three survivors of a Himalayan airplane crash--a woman, her husband and her lover--have just two useable canisters of oxygen. This could be the premise for a short story or 80,000 words.
A full-length novel would have emotional backstory, blow-by-blow action of keeping warm, stopping bleeding, frostbite, the relentless deterioration caused by oxygen deprivation. Who will be sacrificed (and how), and what life will be like for two of them after they are rescued.
In this disaster example, the crash and survival are technically interesting. More interesting will be the emotional fencing between the lovers. The lies and confessions. Whispered conversations and eavesdropping. Whom does she love more and why? Who will betray whom? Who will panic first? Will the truer love sacrifice himself to save her?
Conflict can be external and internal. "Mary Buckham and Dianna Love say your heroine "should not be able to reach her External Story goal (being rescused) without making a major internal change. Each conflict should force her out of her comfort zone to make changes in degrees, then escalate to a climax far greater than the first conflict."
A story starts at a beginning: hero and heroine in a setting have a problem. We write their journey throwing up obstacles and hurdles, knowing it will end at a HEA. I am watching my character arcs as closely as my story arc.