>>714629695
Pick a game and play! That aside, I'd say pic whichever one looks the most interesting/has the characters you want to learn about and go from there. The modern games have easier difficulties for beginners to ease themselves into the series, and having the option to do side battles to better level your troops. Older games tend to be more ridged, with the occasional side maps but other than that, its just you and your units against an army.