Add workshop 0 summary and a bit of context

Author: pavlenex

merchants/design-sprints.md

@@ -2,12 +2,10 @@
 
 [INSERT COVER IMAGE]
 
-— [Design Sprint Board on Miro](https://miro.com/app/board/o9J_kh9LoWM=/)
-
-—[LINK TO CALLS]
-
 ## Introduction
 
+The goal of the Bitcoin Accepted Here design sprints is to provide a clear use-case or an example for abstractions we've discovered during our research. These sprints are heavily focused on merchants who accept Bitcoin payments.
+
 - [COLLABORATION]
 - [PROBLEM STATEMENT]
 - [RATIONALE]
@@ -36,3 +34,18 @@
 ## Continuity Plan
 
 - TBD
+
+## Design Sprint Board
+
+The design board for sprints is [available on Miro](https://miro.com/app/board/o9J_kh9LoWM=/)
+
+## Calls, workshops and sprints
+
+This section provides a hierarchal order of the design sprints calls and their brief summary.
+
+### Bitcoin Accepted Here: Merchant Design Workshop #0
+
+Video summary of the call is [available here](https://youtu.be/OGrzjl8A5vg)
+
+On the call #0, we've put ourselves in a position of the merchant accepting Bitcoin payments via [BTCPay Server](https://btcpayserver.org) We defined BTCPay Server, the core functionalities and type of users who may use it. 
+We defined BTCPay Server as a Bitcoin payment infrastructure, that is thanks to its flexibility similar to the WordPress. BTCPay Server is the WordPress of Bitcoin that allows users to create invoices quickly, get paid and process refunds. Our focus was on online merchant persona, with limited or no access to the banking infrastructure. We've determined that troubleshooting was a big issue due to the amount of steps involved and technical knowledge a merchant needs to posses in order to troubleshoot a payment related problem. The conclusion was that payment processing is not something merchants visit frequently, unless there's a problem that they need to troubleshoot. That's the reason we tried to aim for making troubleshooting and refunding easier.