Congratulations on your decision to start an online business!
There are many great books available on how to start an online company.
One of them is "Starting an Online Business for Dummies" by Greg Holden. You might also try "The Complete Idiot's Guide to Starting an Online Business" by Frank Fiore. The slightly tongue-in-cheek titles notwithstanding, there's some good content to be read in these two books.
Good luck on your new business,