If you dont know anything about Circuits, I believe youre not confident with any of the Chapters be it, Current Electricity, Electrostatics, Capacitors, Magnetism & Electromagnetism. For now, leave magnetism, prepare Current Electricity strongly followed by Theoretical, Formulae and Previous Papers Revision from Electrostatics, after this prepare Capacitors Topic well. I would suggest you to refer the following Material for Preparation.

1. Any JEE Physics Textbook. Briefly revise theory, formulae, solved examples. Ex. DC Pandey/TMH Comprehensive Physics JEE Main.

2. Arihant Physics JEE Main Crash Course Book. Solve the Respective Chapters.

3. JEE Main Previous Years Papers. Solve all the Circuital Questions. If no time, just see the Solutions, and memorize or note down how the different problems are getting solved. Try to reverse engineer and note down the important concepts getting asked and practice similar circuital problems.

Youtube comes to great rescue in times like these. You may follow Physics Videos of Vedantu, JEEnlight or Physics Wallah for revising particular JEE Physics Topics completely. Once done with these, move over to Magnetism.