In the first two pictures, your safety lever is to the left (in the "fire" position), and the cocking piece is in the fired position. Safety will not swing up until the rifle is "cocked". In your second two pictures, the safety lever is straight up - the middle position. You should be able to open the bolt, when safety in this middle position. Safety is fully "on" when the safety lever is pivoted to the right - the cocking piece is held back and the bolt should be locked shut - should not be able to open the bolt with the safety in the fully right position.
Start with your first picture - open the bolt, pull it back, push it forward and close the bolt. The cocking piece should be protruding rearwards like in your third and fourth pictures. Your rifle is "cocked" and ready to fire if a cartridge were to be in the chamber. If the cocking piece is not protruding rearwards, it has failed to engage the trigger sear and you need to attend to that. If it is protruding rearward, you should be able to move the safety lever from the left position, to the vertical position, and then on to the right position.
As has been mentioned previously, you can not engage a mauser safety, unless the rifle is "cocked". In picture one and two your rifle is not cocked - the cocking piece is in the "fired" position - that is the "sizeable piece of metal blocking it".