The root starts with a body on a horse: to ride. From riding comes the rechev (vehicle) and the rakevet (train). Then the idea climbs one level of abstraction: to mount parts onto each other is to assemble, so the same root gives you the components, the composition, and anything complex (literally "put-together"). Hebrew even mounts glasses on your nose with this verb. One root, from a horse to a chemical compound. Every entry is verified against pealim, niqqud included.
The same root runs through the verb system. Each binyan is a voice: it bends the one idea into active, passive, causative or reciprocal. Tap to hear.
The two verbs show the root's two altitudes. Pa'al is the literal one: you sit and ride. Hif'il is causative and abstract: you make parts "ride" on each other, that is, you assemble, and idiomatically you mount glasses onto a face. The reflexive hitrakvut (chemical bonding) survives as a noun. Other binyanim are not lexicalized here.
Same root letters, different noun moulds (mishkalim). The mould tells you the function: who does it, the act of doing it, or the thing produced.
Strip the prefixes, suffixes and vowels. Three consonants remain, and the meaning lives there.