RECORD A SIMPLE EXCEL MACRO

Working with a large Excel database, I need you to develop a macro that will select 30,000 rows of data. There will be 25,000 groups of 30,000 rows. The macro will require my ability To position my cursor at a particular cell (i.e. A30000) and run the macro so that it will select the next 30,000 rows so I can then copy and paste it elsewhere. Additional macros will be needed in the near future.