FSX Airport- Adding new taxiway and AI help

Hi. My hometown airport isn't what I was hoping it would be on FSX. A few years back, they added a taxiway, larger parking area, and a fuel depot. FSX has none of these, and the runway dosent have the right side markings or the VASI lights we just installed last year. How can I use AFCAD 2.21 to edit this? Also, I would like to have a few Cessna's at my airport. We have an average about 15 planes in/out a day and I'm the only one there on FSX
Also, If I make the apron bigger, a few pine trees will be on the tarmac, how can I remove these?
Thanks,
-Alex

Thanks,
-Alex