The Roman poet Ovid, in his Metamorphoses, Book X, relates that Pygmalion, a sculptor, makes an ivory statue representing his ideal of womanhood and then falls in love with his own creation, which he names Galatea; the goddess Venus brings the statue to life in answer to his prayer.
A prepositional phrase is such a phrase which begins with a preposition (on, under, over, etc) and ends with a noun, pronoun, gerund, phrase etc.
So here, the correct sentence will be "On the stage the members of the orchestra began to tune their instruments".
It means the way the writer uses the language to convey meanings, feelings e.t.c. In another context it may mean the way the writer uses language in order to manipulate the reader and lead him where he/she desires e.g. to feel in a certain way about a character, to have certain expectations e.t.c.
