In Frankenstein, what has the creature been doing for the two years since Victor gave him life, and why does he go to Geneva?
In his narration, the creature tells Victor that after he stumbled out of Victor's apartment on the night that Victor brought him to life, he wandered around for a while, trying to become accustomed to the physical world. He is similar to someone waking up from a coma who has to relearn how to talk, walk, and sometimes remember. He tries to get food from a village, but he is run out of the village, and this (in addition to Victor's abandoning him) causes him to learn that mankind does not like his appearance. He eventually makes his way to the woods near the DeLaceys' and begins to watch and learn from them. Shelley implies that this is where the monster spends most of his time between his creation and his journey to Geneva.
When the creature is run out of the Delaceys' cottage, he discovers that he has Victor's journal in a coat that he took from Victor's apartment. While this is too coincidental to be believable, Shelley employs this suspense of reality (a common Gothic element) so that she can explain how the creature finds Victor. The creature uses the monster to find the Frankenstein family in Geneva. His goal in going there is to talk to Victor and to ask him to make him a female companion.
One note here, the two-year time span is somewhat questionable. Shelley mentions two years, but then later Victor states that he has been away from Geneva for six years. There is no way to reconcile this; so it seems to be a discrepancy on the author's part.