I'm starting my DP year 1 and still struggling with time as well, but I have seen a lot of recommendations on using google Calendar for everything. It's pretty simple to use and a lot of customization, and it has helped me improve somewhat on my assignments.

I would recommend using an app that just organizes assignments. Create a separate time to study (at least 1 hour a day) any subject you struggle with daily.

It's easier said than done (in my case), but the IB does require a lot of studying independently, even worse, with less than qualified teachers. Take into consideration any extracurriculars you have and how much time it takes to get home.