No, not a problem. Just follow the rules as on page one of this thread. You don't need the addon. You need to set the start date as
manual in the 'workshops' and set all the other settings as required depending on whether you want to fly as an A, B or C type. Your start date would be today's date but in 1916. Once you have flown a sortie you can capture the results in the URL below, putting your name in the 'other' field. Once I see you as a Campaign pilot I will add you to the list.

Just follow the rules as set down by Olham in page one of this. It doesn't matter that you start after most of the others. Have a go!

LG 27" 27mp65 monitor; EVGA GTX970 GPU; AMD Ryzen 3500 CPU; Corsair 750w PSU; MSI X470 mobo

RAF 1966-73 Cpl Engine Fitter (Retd.) Trenchard brat 206th Entry
DBA and systems programmer 1981-2005. Now retired since 2014