How to lose weight in 3 months?

I need to lose weight in 3 months.. what should i do to lose the weight?… what should i eat? and what excercises should i do? please help me lol im new to this …. also i know you have to lose weight all over but im looking to lose weight on my legs mainly

i weigh 145

ALSO how many pounds will i lose in 3 months? estimate or tell me what you know
thanks !