When Julius Caesar sought to reduce the overcrowding in the Forum, he started the practice of creating additional spaces adjacent to the city center. The practice was followed by Augustus, Nerva, and Trajan, creating the several imperial fora which lie just to the north of the original Forum. Caesar selected a site off the Argiletum, bounded on the south by the Clivus Argentarius and the Curia. The cost of the land was reported to be 100,000,000 sesterces. The Forum of Caesar became a place for the Senate to conduct business and for the offices of the Secretarium Senatus. Along the south side of the forum, up the Clivus Argentarius, were two levels of shops.
Caesar started acquiring land for the Forum in 54 BCE, and work began three years later. The dedication of the forum and temple took place on September 26, 46 BCE, the final day of Caesar's triumph. Augustus does claim to have completed the complex in the Res Gestae, suggesting that there was still work to be done after the dedication and after Caesar's death. In 113 CE, the forum was rededicated by Trajan after work done under Domitian, and it was rebuilt after a fire in 283 CE under Diocletian.
The forum was 115m by 30m with a wide central area flanked by two narrow porticos (see this model). At the far end of the forum stood the Temple of Venus Genetrix. In addition to statues of Caesar and his horse (which you can learn more about by clicking on "Equestrian Statue"), a colossal statue of Tiberius was added, donated by residents of Asia Minor after Roman earthquake relief in 17 and 23 CE.