A Cardinal Number is a number that says how many of something there are, such as one, two, three, four, five etc...
It does not have fractions or decimals, it is only used for counting.
An Ordinal Number is a number that tells the position of something in a list, such as 1st, 2nd, 3rd, 4th, 5th etc.
And Yasmin is 2nd and Rob is 3rd.
An nominal Numbers is a number used only as a name, or to identify something (not as an actual value or position)
In this photo there are 6 cars. Car Number "99" (with the yellow roof) is in 1st position: