Fill handle

Hi Can any one help me please.
I am trying to get numbers in a column to follow each other by dragging down instead of having to type them all in does anyone know haow to do this??? example below might help if i haven't explained myself very well - thanks in anticipation of any help...

1
2
3
4
5
6
7
etc
etc

You only need two numbers; put 1 in the first row, 2 in the second row, select both cells, and drag the fill handle down.

so simple but saves loads of time - thanks