Second build...A virgin no longer. 😉
As has been said magnets won't do any harm, you'd need some seriously strong ones to effect a HDD, and other components are immune to magnetism.
As long as parts are inside their protective bags/plastic casings static isn't likely to be a problem, unless you hook yourself up to a Van de graaff generator that is.
You already know:
DON'T PANIC! If it doesn't boot first time, it's not as bad as you think.
READ THE MOTHER BOAD MANUAL, you'll be surprised how many issues are caused by a simple assembly mistake, usually not connecting a cable or component correctly.
Plan your work, work your plan, install logically: Motherboard standoffs in the case first, then motherboard backplate, then CPU, then CPU cooler...You know.
If you are worried about static, ground yourself during the build, ANY solid object connected to the ground will do: A masonry wall (brick or concrete (cement)), a water pipe or any type or any grounded electrical appliance if it's plugged in.
Use only good quality, well fitting tools, avoid cheap 'bargain' ones, they're just poor quality and can easily damage screw heads, or even slip and wreck an expensive part.