howdy! and welcome!
first step - do your homework - do some reading so you understand basics, safety precautions dealing with nicotine base, mixing... hop in the DIY forum area, some great folks and great advice there...
get a recipe or two that you know you (might) like - much easier as a starting place than just ordering flavors that sound yummy and starting from scratch - get a feel for how things taste (same types of flavors from different vendors can have VERY different flavor profiles)
ask questions!