Shopify Edits .pdf

Currently When someone purchases or ‘Adds to Cart’ they are then instructed to open account, pay
with credit card and then fill out a form with all the details.
I need to stream line it all so the experience as a whole.
We are going to be directing our customers to do the following
Add to cart -> Open Account -> Upload details -> Purchase
So I need the process to show as below.
After the initial ‘Add to Cart’ button is pressed it to redirect to the below screen.

After ‘Sign Up’ button is pressed it redirect to the POWR Form (this was previously filled out after
the purchase)

After the ‘Submit’ button is pressed it redirect to the below screen.

We will also need when someone logs in (after previously have purchased the 5 pack bundle and
have existing credits) for them to ‘Add to cart’ then be directed to ‘POWR Form’ (as they will not
need to re-sign up so this step would have to be removed for someone that is logged in) and then
‘Submit’ -> ‘Purchase’ like normal.
Also if someone purchases 2 individual brochures for example they will have to fill out one form and
submit it then be directed to a second form submit it and then be directed to the final purchase
page.