G'day and Welcome Josie
You've made the first big step on that journey to health and fitness by finding your way here. The place is full of inspiration, motivation and knowledge.
I'd say make yourself a plan - a road map to your destination. List the foods to eat, the quantities to eat and the foods to avoid. Find modes of exercise that you are comfortable with. Have targets along the way so that you can feel proud of your progress and know that you are getting closer to your goal.
Now get to it!