I can only share with you my own understanding of Sikhism, it was started by Guru Nanak devji as an alternative to the religions of the time. At that time most religions were mired in ritual, mostly misunderstood by the common man, and on the whole adopted the carrot and stick approach to living, ie, do this, do that, and you will go to heaven, not be reborn, etc. The religions were run by an elite who preyed on the lack of understanding that was common and inevitably manipulation took place of people who did not know better.
So Sikhism stood for a direct relationship with Creator without the need for a clergy, for no rituals, no carrots, no sticks, no heaven, no hell and finally, death. The object was to live a life that was content and accepting, but also to help others who needed help, not in a demented help all fashion, but to use logic, discretion and wisdom to educate oneself in the ultimate truths of the world in order to give heightened perception and understanding.
Spiritually, it is believed that if one is in consonance with ones surroundings, then that feeling is not unlike heaven, but once achieved, it has to be maintained, every day, every hour.
just my own understanding