Ok this is called "Cell Wrapping"
Select the cell you have all the writing in
Next select "Format" (this is located at the top of the screen in the same menu as File, Edit, View, Toolbars etc. etc)
Once you have selected format then select "Cells"
(a new window should apear with a series of tabs running along the top of it called: Number, alignment, font, border, patterns and protection)
Select the Alignment tab
You should now see on the left hand side of the new window three tick boxes labelled "wrap text", "Shrink to fit" and "Merge Cells"
Check the box labelled "Wrap text"
Select OK from the bottom right hand corner of the window
You should now find that the text fits into one cell and that the cell will change its size to fit the text.
If you find that the cell is too thin and tall or too wide and short then you can manually adjust the size of the cell to your desired size.
You should notice that the cell references (i.e. the row number and colum letter) are orange on the activated cell. in order to manually adjust the size of the cell you have selected (a.k.a. the activated cell)
Move your mouse so that the cursor (white cross) is hovering over the orange column letter.
If you now move your mouse so that the cursor is hovering over the line inbetween two columns you should see the cursor change from a white cross to a balck arrow pointing downwards. once it is pointing downwards hold your left mouse button down and drag it to the right. you see the collumn expanding in size!
This same principle follows for when you want to adjust the height of the column
If you find that a cell is too big for your text, a quick way to get the cell to fit the size of your text is to hover you cursor inbetween the two collumns so that the cursor turns to a black arrow again and double click. This will automatically resize the cell to fit the text within it. ( note the cursor must be a balck arrow in order to do this.
Hope this helps