The press secretary explained the blueprint of the plan to the press corps.
Literal
Press-officer [subject-が] that plan [possessive-の] blueprint [object-を] press-corps [to-に] explained
青写真 (あおじゃしん) literally = 'blue photograph,' a calque of English 'blueprint.' Used both literally for architectural plans and figuratively for any detailed scheme — the same metaphorical extension as in English.