An OC is an organised crime (found here) where faction members form a team to complete a crime. We do these as they are an easy way for members to earn cash for themselves and the faction along with gaining easy respect for the faction
Here is an example of what an OC will look like:

In this screenshot I've circled 3 important details:
Yellow: The crime level which in this example is 7 (you'll need this to request specific OC spawns
Blue: The role name (this is important as you'll read further down)
Red: Your CPR for that specific role when the role is empty (if the role is already taken it will show that players CPR)
Once you join an OC it will change from recruiting and enter planning stage with a timer of 1 day for each member needed for the crime. Most crimes take 3-6 days of planning. You can only join 1 OC at a time and you may fly or anything else you like during this planning stage but you must be in torn and okay (not flying or in hospital) when the crime is ready for completion. Fines are in place for anyone who repeatedly delays OCs from completing (details can be found here in faction rules)
Some OCs require items to be held by certain members in certain roles, you can check if you need an item by clicking the ? Before the role name (dont worry too much as these are provided by the faction just don't sell it if you are sent one).
So which crime do you join? This is where it gets a little more complicated. Our faction has minimum CPRs in place and each OC has a role priority order calculated to maximise chance of crime success. As this is supposed to be a basic guide up to date details for this can be found by clicking here.