When on the checkout page complete steps 1-7 in sequence.
Or see simple steps below:
Step 1.
Add parts to cart.

Choose to "Collect at warehouse" or "Send by courier"
Fill in the "Checkout Page"

******Depending on your card/bank you maybe set up for extra Authentification(SCA / 3D Secure) and you may be sent from your bank a passcode to confirm your purchase
Now wait for confirmation email and after that all updates will go to your email address