macro to copy data into 1 sheet and sort

[neowok]

Having some trouble with a couple of macros.

I have the attached file which different people populate each day with various data. What I need to do is create a macro which will blank the Master sheet (from row 4 downwards to keep the headers) then copy all of the individual sheets (for as much data that is on it, excluding rows where the Location column (J) is blank) into the Master sheet and then sort the master sheet into date order.

Then one more macro which will copy any rows between the 2 dates in cells K1 and L1 on the Master sheet into the export sheet.

I have attached 2 buttons to the master sheet for the Macros. I have had similar macros in the past a few years ago and they are relatively small and simple, but after going through them now I just can't work out what its doing well enough to make it work for this so any help would be appreciated.

thanks