@Nim ****
, seeing as it's your first time you can't use the online program AND you're too late to mail it in too (has to be postmarked 14 days before your due date).
You DO go to Chaengwattana and can't use Cham Churi.
BUT
you don't need to take your dependent with you and can do a 90 day report for them without a problem with just their passport and a filled out TM.47 form