Your teacher produced a special light-sensitive photo paper by soaking the paper with a solution containing a mixture of potassiumhexacyanoferrate-III and ammonium ferric citrate.

If You touch the paper please wear gloves!

Making a picture

Take a water sprayer and a sheet of paper and make the paper humid (not too wet). Put an object (e.g. leaves, grain,….) on the glass plate of an overhead projector and put the humid paper above it. Cover both with an old newspaper and a weight ( e.g. a glass plate).
Switch on the light of the projector and allow to irradiate for at least 10 minutes.

Fixation

In order to remove the rest of the light-sensitive substance it has to be dissolved. Prepare a basin containing 1-M hydrochloric acid. After irradiation put the paper for ca. 5 minutes into this bath.
The final process is called watering to remove all the small rests of chemicals.
Take another basin with water and allow to water the paper for another 10 minutes.
Finally dry the paper.