what is the order of chapters in maths physics and chemistry for jee mains dropper for preparing

as you know jee mains is as easier exam as compared to jee advanced. You need accuracy and speed and must be well cleared with the basics. Lets proceed,
Regarding Physics- I think hc verma is a must book as it deals with concepts from basics to advanced. Well a few topics regarding mains is not complete so you can go for resnick, haliday and walker though its your choice and 40 years is must book you must solve each chapter as it gives you an idea what is asked. If you have joined classes then coaching materials are good.
Regarding chemistry- Ncert textbooks are must for jee mains . They are more than enough. After that 40 years is a must book for mains as well as advanced.
Regarding maths- Ncert textbooks only for basics and few mains topics. As there is no perfect recommended book for maths still there are many options you can go for arihant two big books for jee mains and advanced or some coaching material. . Lastly 40 years is a must book.

You must finish your mains syllabus till December or else you will have a problem in handling boards as well as mains. Mains requires speed so practice as much tests as possible to maximize your speed and score. You can join test series for that. Set a target according to your level . Lastly performance is directly proportional to hard work.
All the best.