1. Aedh (He) Wishes for the Cloths of Heaven
HAD I the heavens' embroidered cloths, Enwrought with golden and silver light, The blue and the dim and the dark cloths Of night and light and the half-light, I would spread the cloths under your feet: But I, being poor, have only my dreams; I have spread my dreams under your feet; Tread softly because you tread on my dreams.

2. Summary
This poem can be divided into three parts: the wish, the offer and the request
He would decorate them with golden and silver light.
He would change night and the light and the half-light into blue, din, and dark color for her cloths.
And he would spread the cloths on her way. But he has only his dreams, so he requests her to tread softly on his fragile dreams.

4. Meaning
In lines 1-5 the speaker is saying, “If I had the clouds in the sky, the colors of the sun, moon, and stars, and all behind and in front of them, I’d put them under you, because you mean more to me they would.”
Or, he may mean (metaphorically) that if he had worldly wealth, he would support the one he loves with the best he has — or, that if he had the power as a poet to capture the glories of the world in the “dreams” he spins, he would dedicate his achievement to the beloved.

5. Meaning
“Enwrought with golden and silver light, ”The blue and the dim and the dark cloths
Here the speaker is describing wealth of which he does not have. “En wrought with golden and silver light” symbolizes wealth. He uses blue which symbolizes royalty.
Although Yeats could be referencing England’s imperial rule of Ireland. The gold, silver and blue could be a juxtaposition of Ireland and England. Ireland being known for it rough history, harsh landscape, and hearty people. Oppose to England, whom is famous for it’s indolent royalty, prestige , and power.

6. Meaning
But I, being poor, have only my dreams; I have spread my dreams under your feet; Tread softly because you tread on my dreams.
He is poor, so all he has to his name are his dreams. He will still give his effort to support his loved one by sharing his delicate dreams with them.
The speaker is hinting at the very real possibility that he’ll be hurt by the person he loves, but making himself vulnerable to them nonetheless.
The “you” here may well be Maud Gonne, Yeats' onetime lover and subject of many of his poems. Gonne turned down numerous marriage proposals from Yeats, and the two maintained a tense friendship for decades