Genesis 10 is a genealogical account of the "Table of Nations," describing the descendants of Noah's sons after the Flood. It outlines how humanity spread and diversified across the earth, forming different nations and cultures.

Therefore, "Hadoram, Uzal, Diklah" are simply the names of individuals, specifically sons (or descendants) of Joktan, who was a descendant of Shem.

Here's a breakdown of what we know (or, more accurately, don't know) about them:

Genealogy: The verse establishes their lineage: Noah → Shem → Eber → Joktan → Hadoram, Uzal, Diklah.
Possible Geographical Connections: Genealogical listings in Genesis often correlate with geographical regions or ethnic groups. This suggests that Hadoram, Uzal, and Diklah were likely the progenitors of specific tribes or peoples who settled in particular areas. While pinpointing these areas with absolute certainty is difficult, scholarly consensus often places Joktan's descendants in Southern Arabia (modern-day Yemen and surrounding regions).
Uzal is often associated with Sana'a, the capital of Yemen. A former name for Sana'a was Azal.
Speculation suggests connections to other regions of Southern Arabia for Hadoram and Diklah, although these are less clear than Uzal's connection to Sana'a.

In summary, the verse itself simply provides genealogical information. Its significance lies in its contribution to the overall picture of the post-Flood world, suggesting the spread of population and the emergence of distinct cultural groups from Joktan's line within the larger Semitic family. We cannot definitively say what role these individuals played in life, but we can interpret that they represented the beginning of tribes and settlements.