How to join tables in excel (vlookup)

Say you have some data, like id, and student names in file a.xls.
And you have id, and date of birth for some students in file b.xls.
How do you add date of birth to file a.xls? (You could use sql, left join ... etc, but, what if you have data already in excel?)

A.xls has the following content, with id in the first column, and name in the second:

1	john
2	bo
3	mike
4	tatjana
5	marko

B.xls has the following content, with id in the first column, and date in the second:

1	31.12.1999
2	14.4.2000
3	18.5.2001
5	3.16.1980

-open both files in excel

-in file A.xls, position cursor in c1 ( top row, third column. the cell and and column should be empty.)
-click on 'fx' in toolbar
-select vlookup

set the following values:
-in the first box, named 'lookup value', enter 'a1', without quotes. It is the first row, first column cell. It signifies data that exists in both files.
-for the second box, 'table array', click on the button on the right of the box, and  select all cells in file B.xls that have data. 
 All of 1st and 2nd column in B.xls, that has some text or numbers in them.
-in the third box, 'col index num', enter 2. It means that you need data from the 2nd column, of the file B.xls. (Matching data will be copied to file A.xls)
-in the forth box, 'range lookup', enter 'false' without quotes.
Click ok

Now you should have date of birth for john in the cell 'c1' of A.xls file.
To repopulate other cells in 3rd column, drag and drop 'c1' cell down.

Save if you wish.