He can't. Similarly, you and also any economist will not be able to explain why it will increase inflation.
Trump's proposing replacing income tax with tariffs, that alone impacts millions of variables and their interactions.
Increased tariffs --> cost passed on to consumers is an unrealistic reductionist NPC way of thinking.
Economists are the astrologists of finance. Put simply, if they had even a 1% edge in their predictions and forecasts, they would clean out every market. I don't recommend putting any stock on what they say. If you back tested their predictions prior to every market cycle, you'd find they are always wrong.
It can be explained but you are clearly incapable of understanding it. It actually is as simple as trade war and increased costs. But never argue with an idiot as they will simply repeat their simple rubbish as they are incapable of understanding the reality.
Ignore button do your thing.