Deleting Blank Rows below data using a macro

[Fingers_9]

I'll try and explain this as best as possible.

I am pulling external data into Excel in order to run some pivots off it. This data will start in cell B1.

Column A contains a key, made up of the contents of this data. (e.g. =B2&F2&H2).

This is then used to match against another tabs.

I would like a macro to firstly, fill column A down to the end of the data, i.e. the last row in column B that has data.

Then I want to delete all of the blank rows below my data.

Any help would be appreciated.