Could someone explain the difference between a Sikh, Sardaar and a Singh?

Sikh is defined in Sri Guru Granth Sahib, as the ones who, as soon as they wake up remember the Creator, take bath and then immerses themselves in the sea of Gurbani.
All day, as they go about performing their daily responsibility, they remember the Creator and live a life of truthful person.
Sardar: is a Persian word meaning a leader. The Leaders of that time wore DASTAR, (Turban). Sikhs are known as Sardars as they were truthful people with high character so the community respected them as good leaders. The Sikhi wore Dastaar (Turban) as well. So it fit right in with their being termed Sardar.
Singh is last name given by Guru Gobind Singh Ji to all Sikhs at the time of taking KHANDAY DI PAHUL (also called AMRITt). Then others are born into Singh family and inherit that last name.
Please note: Singh is not unique to Sikhs. The “Singh” was a last name for some Rajput before Guru Gobind Singh Ji gave it to the Sikhs. And Rajput, who are Hindus, still use Singh as their last name.
So not every person with last name as Singh is a Sikh.