I’ll suggest you to take a diagnostic test first. If not, then also it’s okay.
In quant, for basics go for
Manhattan prep books.
Once you have done your basics, then go for official guide (i suggest you to practice questions in exam mode)
Now, it’s time you must take a mock or something to know your weak and strong areas.
After giving the mock, analyse every single question, (if a question is wrong, why it’s wrong, where you have gone wrong, was it a conceptual gap or careless mistake)
Go back and work on your every weak area.
After complete OG questions, you can buy more question from some prep course, or you can also solve questions from gmat club itself.
Continue practicing until you reach your desired score.
Don’t forgot to take a break.
Good Luck!
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