Open the bolt. Remove the magazine. Set Safety to “Fire”. Press the bottom bolt release & pull the trigger. Then remove the Bolt.

Use a third party host for pictures. I use https://imgbb.com/ It works very well and is quite easy to use.

Surface rust is normal on many boxed firearms. Once removed, simply use some gun oil & 4/0 Steel Wool to remove the rust. And just keep it lightly oiled.