2 under 2

I dont post in here often, but I had Scarlett June 17th, 2019 and found out I was pregnant with baby #2 just before her first birthday. I gave birth February 11th, 2021 so my June baby is finally a big sister!! She did great at first and is still very very sweet and helpful but how on earth do I deal with the tantrums? She cries every time we lay her down at night now instead of just going straight to sleep. How do I fix that? Do I yell at her? Hold her like she wants? Is is just a regression from the new baby? I dont know the best way to parent her. I dont want to be too tough on her but I dont want her to think she can do whatever she wants. I'm trying to figure out what's worth the yelling and what isnt but it's so hard. Any tips/help would be greatly appreciated.