as for paint, go with a two stage urethane. base coat, clear coat. beginners can also have good luck with single stage if its a solid color. the car's black right? single stage will be way cheaper and will hold up just as good.
dont sand a panel until youre ready to spray it. it should be sanded, scuffed, cleaned, taped off, sealed, based, cleared. in that order, all at the same time. none of this sand it, pretend-prime it and not finish it crap.
since youre already past that point, get it painted fast. any primer that you got from a rattle can is most likely laquer based, and will absorb moisture from the air after 8 hours. it will transfer said moisture directly to the panel, and it will trap it there. right under your new paint. keep the final grit at 500 or higher, and you wont see the scratches in the finished product. its all about the foundation you build your house on.
94 V8 on 17" custom paint, R.I.P
97 Mark VIII LSC yeah
08 Ford Edge, white for now