Excellent article: System design with examples by @SubhadipNandy

Part 1 : https://www.facebook.com/notes/subhadip-nandy/an-introduction-to-systematic-trading/1280291088694632

Part 2 : https://www.facebook.com/notes/subhadip-nandy/designing-a-trading-system-part-2/1288861641170910

Part 3 : https://www.facebook.com/notes/subhadip-nandy/designing-a-trading-system-part-3/1291220327601708

Part 4 : https://www.facebook.com/notes/subhadip-nandy/designing-a-trading-system-part-4/1300757916647949

Part 5 : https://www.facebook.com/notes/subhadip-nandy/designing-a-trading-system-part-5/1302213813169026/