I Want to Write a Book

i would love to write a self help book for dealing with anxiety/depression .. for those who know me, you'll know i'm still fighting the everyday battle of anxiety/depression, it's been a long journey and there's much further to go but i know that in time and with help, love and support i will reach my goal, my goal of happiness, looking back 5 years ago it doesn't seem real how far i have come and it's only now i realise that, yes, i have bad days, days when even getting out of a bed is a struggle, where the thoughts haunt you, but i hold on to hope :) and to write a book, even too help one person would make it worthwhile, a book that someone in need can open and know that they can get through this, to hold on to that little glimmer of hope and never give up, a book full of quotes, pictures, the everyday struggle but with a positive energy attached to each page, for them to realise they're not on there own and there is hope, support, love out there for each and everyone. the problem is - is it a silly idea? - how do you even go about writing a book? the questions are endless!
also i would just like to say for everyone who is currently writing a book or thinking about doing so, i wish you all the best, you can reach your dreams. :)