To solder, you need Solder badge.
Fumes cause damages to your health
Non-lead-free solder and flux contain toxic materials, and the fume from soldering causes damages and illness.
Soldering iron cause fire
Flux is toxic
High temperature causes damage to the circuit and components
Keep clean your work space.
Inspect soldering iron before use.
Solder in a well-ventilated area.
Use lead-free solder if possible.
Unplug the soldering iron when not in use. Use soldering timer switch.