Twitter - How to change names

In Twitter there are multiple names. The names can be displayed to all users as follows:
----------------------
My Display Name
@myname
----------------------

On some mobiiles, the Twitter interface would only allow you to change the first line of name.
To change that first line name, here are the steps.
1. Open the Twitter app
2. Touch on the 'Triple vertical dots"on the top right corner - this will display a drop down list
3. On the drop down list on the top right, touch the first line - which is showing the current name.
4. On the new page, touch the "Edit Profile"
5. On another new page, touch the "Name" field to edit.

The steps above only allow the first line to be changed. So now it can be something like:
----------------------
My NEW Display Name
@myname
----------------------

So the second line with the @ sign is not changed yet. To change this, go to a Computer, then open a Browser.
1. In the browser, go to Twitter's website.
2. Login to your Twitter account.
3. Click on your icon/photo on the top right corner
4. In the Drop Down list that appears, click Settings.
5. In the Settings page, click Account on the left navigation panel
6. The main panel in the middle will show Account, and under it is a text field for Username.
7. Enter the new "Username" and this would appear with @Username.

8. In addition, go back to the Home Page
9. Click on your icon/photo on the top right corner.
10. Click on the first line, which shows your name.
11. This opens a new page. Click on the Edit Profile,
12. Then fill in the text field that pop up - this would be the first line name.

----------------------
My NEW Display Name
@NEWusername
----------------------