GMAT Verbal Section | Re: Improve grammar

Hi All,
I want to improve my grammar right from the basics, since I am a non native speaker of english my command on the language is not that good, especially grammar.
Can you pls sussgt how can I can improve english grammar, for SC questions. currently I am working with a high school english grammar book (wren & martin) and ultimate english grammar book by gmat club, not sure it that will suffice for SC questions.

Thanks for help, in advance

Cheers !!!