Hi Opie
NCdiver is right, the dives will automatically go in cronological order. You can erase all the dives that come pre-loaded in the log by oceanic to make your dives the only ones in the list (which you probably already did).
On the left side of your dive log under configuration you should see personal. click on personal. at the bottom of the new screen there should be a bar that says configuration on it. Under that bar is the "beginning lifetime dive number" (if you don't see it you may have to click on configuration to open the drop down). Change that number to the dive number you would like your log to begin with (so if you plan on entering all the dives you have ever done you would want this number to be 1). This should correct your dive number problem as long as you have the dates and times correct.
For the time in/out, enter the time in and the elapsed dive time. The time out should change on its own. If you are unable to click on those fields and change them, then I'm not sure what is going wrong.
You should be able to write anything you want in the "pdc model" field while you are entering your dive (left click, delete and type in what you want). I'm not sure why its not allowing you to.
Be sure you are clicking yes on the "do you want to save the changes" box after each new manual entry.
All of this is assuming that you have begun by clicking on the "add/download new dives" at the top of the page (red plus symbol), selected manual entry dive, and clicked okay.