There is a lot to know about sikhs like what they where they come from and how it all started but because there is a lot of info lets shorten it out so you can understand it very well and have a basic understanding
the first question is how did it all start? now lets set the scene.
The Sikh faith began around 1500 CE, when Guru Nanak began teaching a faith that was quite distinct from Hinduism and Islam. but thats a brief description so check out the start page for further more detail.
question two what are they wearing on there heads?
Well the thing on there head is actually called a turban or to be precise a sikh turban that dates back to Bai-sakhi of 1699, it also means a lot to them because it makes them stand out of the croud and also fun fact sikhs are allowed by law to where a turban not a helmet on a motor bike.
question three what is there holy book?
There holy book is called a Guru Gransahib and is treated like a living person but not food on it, they also fan it and when they celebrate vasaki they have a constant reading of it all day long.
question four what is vasaki?
Well vasaki is a festival that anyone can join that gos 3.5 miles long, the crazy thing is that they walk it with bare feet and they clean a flag/flags with yogurt, more info on the vasaki page.