4.
To specify a minimum number of repetitions, in the Min Count box, type the number. If this option is set to 0 and no data is provided for the objects in the subform at data-merge time, the subform is not placed when the form is rendered.
5.
To limit the number of repetitions, select the Max option and type the maximum number of repetitions into the associated box. If you do not specify a value in the Max box, the number of repetitions will be unlimited.
6.
To specify a set number of subform repetitions, regardless of the quantity of data, select Initial Count and type the number of repetitions you require in the associated box. If this option is set and either no data is available or fewer data entries exist than the Initial Count value, empty instances of the subform are still placed on the form.
Note:
The value in the Initial Count box must be between the Min Count and Max values. If the Min Count value is not specified or is 0, the Initial Count value defaults to 0.
See also 

To create a repeating subform