Top horizontal is the 一 radical. It is the roof or yoke under which the twin sub-bodies hang; xinhua indexes 两 under this single cap stroke, even though the rest of the character carries most of the meaning.
The down-opening frame under the cap delimits the twin inner pieces. Historically 兩 pictured a balance with two equal weights hanging from a yoke; this frame is the supporting bar that holds those weights in place.
Inside the frame sit two parallel 人-like figures rendered as 从. They represent the paired hanging weights or coins on each side of the ancient balance, which gives the character its core meaning two, both, a pair.
