What type of workout when you are just starting out?

Here is a little background on me:

Age 36, female, just had my fourth baby (and fourth c-section) 4 months ago. Haven't exercised for quite some time. Currently weigh 154, goal is 120. I am 5' tall.

I joined a gym a few weeks ago and am aiming for 45 minutes of cardio each time and have also used the weight machines but am not sure how much I should be lifting.

I keep reading advice about lifting heavy weights vs focusing on cardio. I know that everyone needs cardio, but I am wondering if I should focus more on cardio at the beginning of my journey in order to burn the most fat, then later when I am closer to my goal weight start lifting heavier weights? Or should I do both now? What would be a good workout plan for someone who is just starting out and not in the best shape? I also don't have time to be working out for hours each day. Thanks!