Are you able to tell me the first time in the Humash where a word can only be understood by the Oral Tradition and not by the literal meaning?

Yes, I can tell you. The very first word of the Torah, "Bereshit," is a perfect example. Without the Oral Torah, you wouldn't even know how to pronounce it properly because the Written Torah has no vowels. The vowel system, the nikkudot, is part of the Oral Torah. Without it, you can't read even a single word in the entire Chumash. But beyond pronunciation, let me give you an even clearer example from the beginning of the Torah. When Hashem commands Avraham Avinu about brit milah and tells him to cut the "orlah," without the Oral Torah you wouldn't know what that word means. Does it mean a piece of the ear? A piece of the nose? A fingernail? The foreskin? You simply wouldn't know. The Gemara explains to us exactly what the orlah is, which part of the body, and how to perform the mitzvah. The same applies to Shabbat. The Torah says "Shamor et Yom HaShabbat" - observe the Sabbath. But it doesn't tell you how. What does it mean to observe it? Do you keep it in your hands? In a closet? The detailed rules of how to keep Shabbat are in the Gemara, the Oral Torah. This is why anyone who claims you can understand the Written Torah without the Oral Torah is speaking complete foolishness. Without the Oral Torah, the Written Torah would be useless because we wouldn't know how to understand even one sentence.