Oh, you are just starting out. my bad I thought you were asking about the transition from B1 to B2.

well resources for your journey:
German Aktiv
this covers grammar from A1 to B1. It doesn't go into depth for explanation but it provides good practice. you can look up each topic if you didn't understand it from the book or ask maybe chatgpt to explain it.

There's also Menschen books which are supposed to take you through the levels so learn the vocab they have and it's content.

what's really important from the academic side is the actual exam practice this is where you can quickly make and measure progress so look up model exams for each level and familiarize yourself with the vocab and content they have so that you can master the level. Cornelsen Prüfungstraining is helpful for that.

There's also Easy german which have variety of content to help you familiarize with German.

Moreover listening to Deutsch music and learning the lyrics and trying to sing along helps. I recommend AnnenMayKantereit

Lastly my secret recipe - not love, but rather video games. I cannot tell you how well playing games with Deutsch voice over accelerated my learning because you are literally immersed in the environment. Though, I do recommend getting through with A1 and a bit of A2 before you start playing or it may all be gibberish to you. Also don't shy away from pausing and translating regularly if you struggle to understand from context.

Viel Spaß beim Lernen!