In your previous question, you asked about the implications of a multi-domestic strategy. The implications of a global strategy are essentially the opposite of the implications for the multi-domestic strategy.
When a firm chooses to pursue a global strategy, it is trying to pursue a strategy in which its operations are essentially the same in all the countries in which it operates. Therefore, its HR department will need to concentrate on finding, training, and retaining specific types of employees. The firm will need to identify the qualities and skills it wants to see in its employees. The HR departments in the various countries will then need to find local people (where applicable) who have these qualities and skills and can function in the firm's corporate culture.
In short, when a firm chooses a global culture, its HR people need to mold employees to fit what the firm wants rather than trying to adapt more to the specific circumstances in each country.