Installing and Authorizing app flow

Shopify Partner
1 0 0



A bit confused about the installation flow. 


From my understanding it goes like so: 


1. take user to install url

2. after user presses install, taken to callback redirect.

3. get access token and verify hmac


My question is in the first step. 


there's two possible scenarios. Do i have to develop for both? 


scenario 1: Store creates account on my site first, then from there I take them to install the my shopify app

scenario 2: Store installs app from Shopify App Store then is taken to my website. 


The problem with scenario 2 is that I wouldn't have an account associated with the Store like I would with scenario 1.