I've been searching everywhere but i do not know how to edit the confirmation email sent when the checkout process is complete.
Where can I edit this?
Its in rules
admin > config > workflow > rules
I would suggest you use this module https://drupal.org/project/commerce_invoice_receipt and then its very easy to modify what gets sent out.
Drop the 'commerce_invoice_receipt' folder into the modules directory '/sites/all/modules/'.
In your Drupal site, enable the module under Administration -> Modules '?q=/admin/modules'.
Setup new Commerce Order display under Store -> Configuration -> Order Settings -> Manage Display '?q=admin/commerce/config/order/display'. Click on the 'Invoice/Receipt' tab. Unhide any fields you want to use in your invoice.
Setup a rule under Store -> Configuration -> Checkout settings -> Checkout rules '?q=admin/commerce/config/checkout/rules'. Then 'Add a checkout rule', you'll find an action called 'Send invoice receipt email' under Commerce Order that you can use.
You can customize the rule to send out any info you need.
[Using Kickstart] you can also find the raw text and tokens for messages here:
install this module https://www.drupal.org/project/commerce_message it will proivde access many type of messages along with their rules. You can configure and add your own message types