Don't know what to do

As

I'm learning day by day that this mothering thing is harder and harder don't get me wrong i love my daughters more than anything I'm a stay at home mom and I devote every minute I can to them and I love it though it's hard I wouldn't wanna do anything else with my time but I have a problem and dint know what to do my oldest girl ray is about to be 2 in February she is such a good girl so sweet to everyone but these past two months have been hell since I brought her sister home it started won't not wanting to wear clothes and would scream throw a fit and try and pull them off now it's whining for anything and everything and constantly wanting me to hold or pick her up now I make sure to spend time and play with her everyday we play in the yard on the trampoline we go around hunting for rocks we do alot together just me and her cause I don't want her to feel left out we have tried time outs but they end up with her screaming so badly and loudly we can't calm her down I'm at a loss of what to do..do inlet her scream? should I sit in the room with her while she throws her fit? I need some help lol any advice from any mommy's will be so helpful!! Tia!💖