What is the explaination of the first stanza of the poem under the greenwood tree?

Introduction:
The lines given for summary are an extract from the poem Under the Green Wood Tree which is the title of a song taken from the play, As You Like It written by William Shakespeare. The play tells the story of two brothers, the Elder Duke and the younger brother, Duke Frederick.

Summary:
In these lines, the singer is giving an open invitation to any one who wishes to join him in the forest of Arden. The singer desires the newcomer to rest under the shady trees and sing a song in such a manner that his voice mingles with the sweet notes of the bird to produce one single harmony. The singer reminds that the life of the forest is free from all enmity and petty rivalries. The only snag in the life of the forest is the unpleasant and unbearable winter wind. If one is brave and willing enough to endure the harshness of the weather, the life of the forest is almost an ideal one.

Now the singer is laying down certain conditions to be fulfilled by one who wishes to come and pass his life in the forest of Arden. In the first place, such a person should have no worldly wishes. He should not be materialistic in his approach and should never run after fame, wealth, power and glory. He should be willing to pass his life in the open atmosphere under the bright sun. He should look for his own sustenance and nourishment and should be contented with whatever he gets to eat. The singer reiterates that the life of the forest is free from all anxieties, problems and difficulties except the unpleasantness of the chilly winter weather.