Helló,
To start with you could look into RL 2 III / 753 covering 01.01.41 to 30.05.41. : Flugzeugunfalle und Verluste bei den Fliegenden Verbanden. You would then go over to RL 10 / 505 and RL 10 /563. .: Kampfgeschwader 40, organisation, ausbildung, einsatz, taktik. A smart move befor going is to look into:
www.ww2.dk hit on Kampfgeschwader 40 to see the work done by others. Buy the book by Barry C. Rosch, : Luftwaffe codes, Markings & Units 1939-1945 and take it with you and have fun for months to come.
good luck.