New painter here and had some questions on best way to paint my tempestus aquilons [warhammer:killteam] [games workshop]

Never painted miniatures before but I just bought the tempestus aquilons. I put the bodies together but left the arms connected to the weapons, and heads, and backpacks off because I don't know what would be the best way to paint them. Do I prime them separately, glue together, then paint as 1 piece? Or any combination of those? I don't know if i can paint faces so I left the heads off lol. Any help or ideas is very appreciated. If this has been posted before or not the right sub please direct me to the right one.