Land surveyors will come out and stake the well on the property as to the location coordinates on the well permit. Once staked, there will be a stake w/ flags on it and a medicine bottle w/ a well location and legals on it. This flag and stake normally will be where the well (well-bore) itself will be located. The dirt people will then come in and stake off the location to the size of what is required for the rig.
Alot of times the surveyor will call to let you know they will be on your land. Timing is up to the company.