These are step by step instructions to Create Custom app and Connect to ECGrid Simplify Connector:
In Shopify Store - note your *.myshopify.com URL (I)
1. Go to Settings
2. Choose "Apps and sales channels"
3. Click "Develop App"
4. Enable Develop apps (Custom/private app) (skip this step if you've already enabled Develop apps)
a. Click "Allow custom app development" twice
=> Customer app available
5. Create app
a. Click "Create an app"
b. Choose an app name, click "Create App
6. Add "Admin API access scopes"
c. Choose "Configuration" tab
d. In "Admin API integration", click "Configure"
e. Choose "Admin API access scopes" (the list is below), click "Save"
7. Install app
f. Choose "API credentials" tab
g. Click "Install app", then click "Install"
h. In "Admin API access token", click "Reveal token once"
i. Copy and save your Admin API access token in a secure place. because it just reveal once (II)
j. In "API key and secret key", reveal and save "API secret key" (III)
In Simplify website
1. Login to customer
2. Move to "My Connections" page
3. Click "Add Connection" button
4. Choose Shopify
5. Input: Connect Name, Your *.myshopify.com URL (I)
**Do not enter the https:// in front of your shopify store URL**
6. Choose "Custom" check
7. Input "Api Access Token" (II), Api Secret Key (III)
8. Click Connect
Admin API access scopes include:
write/read_orders
write/read_products
write/read_customers
write/read_inventory
write/read_merchant_managed_fulfillment_orders
read_themes
read_shopify_payments_payouts
Here is a video showing the steps to setup the integration.