The courthouse is at:
1225 Fallon St
They are typically held at 12:30 pm
Right now, it looks like there are 352 Oakland properties that are scheduled for auction. These are a combination of single family homes (condos, townhouses, detached homes), residential income and commercial properties.
Do note that although a property may be scheduled for auction, many of them are postponed or canceled by agreement with the lien holder. Reasons could be that the property is being sold as a short sale and the lenders themselves asked for the postponement, or the property owner was able to get a loan modification, or the property owner was able to bring the accounts current, or the owner may have filed for bankruptcy.
It's best that you go to the county courthouse --- observe the proceedings first to get an idea of how to bid.
The county public records may also have the information available that shows which property will be at auction on a specific day.
Search oaklandnet.com for a directory to determine where you need to go for specific purposes.