信号を待って下さい

横断（おうだん）- 'oudan' is 'crossing'

者（しゃ）- 'sha' is added to mean 'person'

は- 'wa' is the subject marker particle

下（した）- 'shita' is 'under, below'

の- 'no' is the possessive particle

ボタン- written in Katakana is 'button'

を- 'wo' is a linking particle from a noun to a verb

押して（おして）- 'oshite' is 'push'

信号（しんごう）- 'shingou' is the noun for 'traffic light'

を

待って（まって）- 'matte' is the verb for 'wait'

下さい（ください）- 'kudasai' is 'please'

Translation: "Crossing person push the button below and please wait for the traffic light."