In the "Form components" subtab, add three components:
"Example First Name" (type: textfield)
"Example Last Name" (type: textfield)
"Example Email Address" (type: email)
Mark them all as "Mandatory"
Select the "E-mails" subtab.
The "Component value:" dropdown now displays "Example Email Address" as an option.
Leave that selected, and click on the "Add" button to the right.
On the next page, you can define the email header and body
Note at the top, however, the E-mail to address: field, that still has your "Example Email Address" component selected. This means that the confirmation email will be sent to the email address that is entered in the Example Email Address form field upon submission.
Click the "View" tab and try out your form: Enter an example name and a real email address, submit, and check to see if you receive the Webform-generated confirmation email.
Under "E-mails", two rules should exist:
First one: with params - to send to the submitter (by using email field entered into the form).
Second param: constant email address (fixed value - website email)
(Basically, adding new field (or in this case, 3 fields - First name, last name, email), then grabbing those values and sending email to the specified email.)