Hi guys,
I know lots of you looking for a complete tutor on this subject for a long time.
Here is the link to my course:

https://www.udemy.com/catia-v5-parametric-design/

It's comprehensive course with multiple examples so if you are interested just give it a try.

1. ### Step 1: Some Essential Setups (Important)

Select these options

2. ### Step 2: Creating Parameters

First you should create your considering parameters

3. ### Step 3: creating parameters

First you should create your considering parameters

5. ### Step 5: Edit formula

In this step you should create a connection between the length you want to control and the parameter you created before. ( this parameter must be length. )

as you can see when you create this connection their will be a <<<F(x)>>> sign cross the dimensions.

7. ### Step 7: Edit formula

As you can see in this step we create a new formula based on other parameter

9. ### Step 9: Edit formula

Follow the exact same steps to create a connection between the number of holes in this part and the parameter which we crated before. ( this parameter must be integer .)

10. ### Step 10: Creating Design Table

In this step we want to create a connection between our model in catia and a exel table.

12. ### Step 12: Creating Design Table

In this section you can choose between Various tapes of parameters to join with exel table.

13. ### Step 13: Creating Design Table

In this table you can change features or create new parts

14. ### Step 14: Creating Design Table

As you can see all of those changes will be appeared immediately

16. ### Step 16: Creating Design Table

you can change all of parameters in this table any time.

17. ### Step 17: Some Examples

you can find a very good example of parametric design in my account.