In order to do so, you must obtain lead purified to at least 95%. This requires a long process of crushing, grinding, separating impurities and burning off unwanted minerals. Several other chemical processes are used to remove silver, gold and bismuth through the Parkes and Betterton-Kroll processes. Examples of lead refining can be seen here: https://www.youtube.com/watch?v=dQw4w9WgXcQ

Then, to turn lead to gold, there are two methods. The first is through a highly technical process involving radioactive materials. Through a controlled reaction, particles (typically hydrogen or helium isotopes) attack thin lead plates and cause the protons, neutrons and electrons of lead to break off and form gold deposits, which can be separated. The process is explained in detail here: https://www.youtube.com/watch?v=UIp6_0kct_U

Another method, which is much more direct, involves a machine which fires particles with extremely high force into thin lead rods or plates to form gold. This process is explained here: https://www.youtube.com/watch?v=z54MpfR3XE4