Dating a man with kids - can you please give me advice?

I am 33F and the man I’m dating is 52 and he has 2 kids (18F and 14M). I have never dated a man with kids and an ex wife before and I am sincerely scared. I love him and im willing to give it a try but I am scared bc i want them to like me, I don’t want them to fear that im trying to be their mom (I just want to be their friend and someone they respect and someone that they can turn to in case of need), and i just us to get along for the sake of their dad as i dont want him to have to choose between me and his kids. I also dont know how to handle the ex wife (kids’ mom). Am I supposed to reach out to her? I also want her to like me… am I trying too hard? What can I or my bf do? Any recs would be appreciated