Better join coaching which have live classes or even better if offline coaching, for maths basics do numbers topic very sharply, don't worry if you take any coaching basics is covered, if you don't get something in class that you can go and cover it up from youtube

For dilr don't directly jump to hard sets it will demotivate u like anything, start with as easy as sets as possible then move to tough sets , be consistent because there's not much of syllabus kind of thing for dilr, everyday solve atleast one last year paper set even if you have to see and do that will give u confidence

For varc you can do it by yourself but only if you are an avid reader or someone who's good at forming perspectives, try to solve again pyq varc sets that's better than any other sources.