In the first stanza of the poem, life is compared to an ’empty dream’ by the pessimists.

Life is but an empty dream!

Though this is not actually a comparison from the speaker’s end, he just hits back to the negative idea of life held by some people who think this life to be unimportant.

Secondly, this life is compared to a ‘funeral march’.

Funeral marches to the grave.

Our life is like a march to the finishing line — the grave. And our hearts beat like a muffled drum in that march. The speaker suggests that we should utilize our limited time span to the fullest instead of wasting it in the thought of death or other such thing.

Then, the young man has compared life to a ‘bivouac’ or temporary camps for soldiers.

In the bivouac of Life,

We have all come to fight and try and win a battle in this world. He urges us not to be like dumb, driven cattle, but to be a hero in the world’s vast battlefield.

Again, this life is compared to a journey on the sands.

And, departing, leave behind us
Footprints on the sands of time;

We should strive to leave behind us a mark of our good work in this life. It is like leaving a footprint on the vast desert of time.

Finally, life is compared to a large sea (‘solemn main’).

Sailing o’er life’s solemn main,

We should set examples before others and inspire the wretched and hopeless people to cross this ocean of life with a brave heart.