I had to write a memo about some new guidelines for weekend employees. This is what I wrote:

To keep our company a safe and worry free environment, there have been several guidelines enforced for employees who work on weekends.

Employees should notify the security officer on duty of their arrival and departure. Offices will be locked until the arrival of employees. It is the employees' responsibility to be sure offices are locked again upon departure. This would eliminate the chances of having an entrance left unlocked. No one other than employees is allowed on the premises, which means no spouses, children, or friends may accompany employees to work on the weekends.

If there are any problems, employees should notify the security officer on duty who will be making regular rounds of the company.
To keep our company a safe and worry free environment, there have been
several guidelines have been introduced enforced for employees who work at on weekends.
Employees should notify the security officer on duty of their arrival
and departure. Offices will be locked until the arrival of employees.
It is the employees' responsibility to be sure offices are locked again
upon departure. This will would eliminate the chances of having an entrance
left unlocked. No one other than employees is allowed on the premises,
which means no spouses, children, or friends may accompany employees to
work at on the weekends. If there are any problems, employees should
notify the security officer on duty who will be making regular rounds
of the company.
In the US, we use "on the weekend." In the UK, it's "at the weekend."

I suggest you bullet the list.

One issue is with "It is the employees' responsibility" -- which employees? When you leave it up to more than one person to do something, each may assume the other did it. You need to specificy which employee, or make it part of Security's job.

Another simply raises a question: Are friends and family never allowed on, so you're reminding them that it applies on weekends, too? Or is it a special rule for weekends. There's some ambiguity there.

Put a comma after "on duty," -- and possible provide the phone number to call. Instead of "rounds of the company" try "rounds of the property" or even "of the premises."