Hey Young
Always at the minimum use a respiratory rated for painting, especially when using hardener (catalyst). I also suggest safety glasses. I had a very small drop of thinner splash in my eye once and was fortunate that the doctor gave me some drops to heal it.
He said it could have cost me my sight. I always prep surfaces with soap and water and Klean Strip Prep All wax and grease remover. I mentioned that product by name because some of the other citrus smelling stuff is not good to use before painting. I find it leaves some kind of a film that repels paint. I etch prime bare metal and use a seal primer on old paint surfaces.. A tack cloth is a must before you apply the paint and never try to hurry the job. TAKE YOUR TIME. It is personally rewarding to see the results of a job well done.
And always, always, always have fun.