To get the best performance from your bike's suspension system it is important to set it up correctly. The general principles for this are the same across all manufacturers. There is no one set up is correct, you should tune the fork for your own riding style whilst taking into account the product's operating window. For Cross Country riding, forks and shocks should be set with 10-20% sag. For Trail riding, Forks and shocks should be set with 15-25% sag.
Please find links to useful suspension setup guides and tools below: