Now.ToString("MM/dd/yyyy") the format can be changed as per your requirement…this gives the current date for you its end date
for start date use Now.AddDays(If(Now.DayOfWeek.ToSTring.Equals("Monday"),-3,-1)).ToString("MM/dd/yyyy") and here as well you can replace the format as needed
In the selector you will have innertext field…add variables inplace of them…you can do that by opening selector in the activity and then right click where you want to add the variable and select the bariable you want to add…
And store the above expressions in start and end variables
<webctrl tag=‘div’ innertext=‘{{startvar}}’ />
This is how it looks…this is a dummy selector… explore selector from ui explorer if not already done…