She is as in a field a silken tent
At midday when the sunny summer breeze
Has dried the dew and all its ropes relent,
So that in guys it gently sways at ease,
This begins the  conceit , which is a form of elaborate comparison, here expressed as a  simile .  It is the only explicit mention of “she” in the whole poem. The syntax of the line is unexpected and archaic, with the “silken tent” placed for emphasis at the end, an example of  anastrophe . 
 The style is taut and spare, no words are wasted. All words, with one exception, are monosyllables, and the line flows smoothly. The metrical rhythm is  iambic pentameter , that is five metrical feet or iambs where a iamb is one unstressed followed by one stressed syllable. 
 Note that this begins the single sentence that makes up the whole of the sonnet. 

The Silken Tent