Written in early spring by william. please help

hey actually this poem is a part of my course and i wasnt able to understand it, any notes on this would really help me. so please if someone can give some notes on it, i will be very thankful.

Written in Early Spring
william wordsworth

I heard a thousand blended notes
While in a grove I sat reclined,
In that sweet mood when pleasant thoughts
Bring sad thoughts to the mind.

To her fair works did Nature link
The human soul that through me ran;
And much it grieved my heart to think
What Man has made of Man.

Through primrose tufts, in that sweet bower,
The periwinkle trailed its wreaths;
And 'tis my faith that every flower
Enjoys the air it breathes.

The birds around me hopped and played,
Their thoughts I cannot measure -
But the least motion which they made
It seemed a thrill of pleasure.

The budding twigs spread out their fan
To catch the breezy air;
And I must think, do all I can,
That there was pleasure there.

If this belief from heaven be sent,
If such be Nature's holy plan,
Have I not reason to lament
What Man has made of Man?

thanks in advance