Need advice for future references

Okay so I’m recently engaged. We haven’t moved in together yet for reasons. We both understand this, and agree that is too priority is getting a place together we’ve been together a month. (I know guys I know super early) he has two kids, 6 and 4. I’m not in their life to replace their mom at all, me and their mom get along great, I do not and will not expect them to call me as such either. they spend quite a bit of time withbtheir mom since their dad works. He gets both of em every weekend. I don’t have kids and just need some parenting advice since I’m jumping in this head first. We have agreed that I’m allowed to discipline the kids as I see fit. (Getting on to them, spanking, etc.) And he backs me up, when I do discipline them. I tend to try and stay away from spankings, cause it breaks my heart when I have to do so, but I want them to listen to me when he’s not around, but I also don’t wanna be the typical mean step parent.