One root spans two ideas that turn out to be the same idea: to gauge / measure and to design / plan. To plan is to measure out a thing in advance; to weigh what will fit. From that come the plan itself, the program, the software, and even the recipe (a measured-out method). A second branch points inward, to the content of something, what it holds when you weigh it up. This is the root behind תָּכְנִית (program) and תֹּכֶן (content), two words you will meet constantly. Every word here 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 everyday verb is the pi'el לְתַכֵּן (to design); the pa'al survives mostly in the old "to gauge / measure" sense. The nif'al is its passive but stays rare. Modern Hebrew did most of the work in the noun moulds below, where this root really blossoms.
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.