You are about to undertake a noble project there. It is one of the least expensive methods to add space to your home; it keeps the same footprint and simply goes upward rather than outward.
Typically the ceiling joists, which in your case would become the second floor joists, are only made of 2 X 6 which would not support the live load of a floor. So, everything from the ceiling upward must be torn off and replaced (it is possible to leave the ceiling joists if you will just add larger joists and close the spacing to 16" centers). With the joists there holding the ceiling in place can be covered with tarpaulians in the event of bad weather.
Now that I've confused and scared you half to death, we would like for you to add several pictures of your house so we can offer suggestions on how to procede.
We are happy to have you on the Forum and will give loads of advice on your project. We look forward to the pictures.