General Information:

Yahweh continues to tell Isaiah what he should tell Ahaz. (See: Isaiah 7:3)

Aram, Ephraim, and the son of Remaliah

The words "Aram" and "Ephraim" refer to the kings of these lands. Also, "Ephraim" represents the northern kingdom of Israel. AT: "Rezin the king of Aram and Pekah the son of Remaliah, king of Israel" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-synecdoche)

This is the name of a man. Translate his name as in Isaiah 7:1.

Here "you" is singular and refers to Ahaz. (See: rc://en/ta/man/translate/figs-you)