firstly you needcthe emulator (v19.8) which you have
next if you plan to do a dx (coloured real looking layout) then you require a program like photoshop
Next as said via fruitemu/the mecca, what is your favourite era in fruit machine playing?
then what machine are you planning to do or remake?
it won't be a easy ride (unless your meme aka socialdragon lol) and if you're willing to learn and take note then you'll be fine.
start something simple first then work your way up, although there has been some recent creators who have succeeded very quickly. I.E amusements aka frig, richy1976 and Evo.
Learn off off the best like Tommy c, Reg, Pook etc and you'll go far
BTW Welcome to this site