OKAY, DO NOT PANIC. They do not assign seats!
Heres the SW drill as best as I can recall. You need to CHECK in EXACTLY at the 24 hour mark before your flight leaves.
You will then be assigned a SECTION, Am B, C, etc.....
They will do PRE BOARDS first, those in wheelchairs
THEN those that have the blue sleeve, (usually medical issues)
THEN those with that Business "guarantee A thing)
THEN if I recall correctly A's..OR they allowed A parent with VERY small kids....then A's, etc etc...
The BIGGEST thing to do with SW is to check in online at the 24 hour MARK and even minutes can make a HUGE difference as to where you'll be sitting, most people go for front.....
Meanwhile, you will very likely sit together, even if one of the adults goes on first and saves a seat (flames???) for the other family member.....
We fly SW all the time, they are excellent, efficient, timely and very consumer oriented (no I don't work for them

) But I do use their rewards program and they are really wonderful, no change fees, no luggage fees and best of all ON TIME very very very often.
HAPPY FLYING , have a GREAT vacation.....by the way, even if you are in a park or hotel at the 24 hour mark, go to guest services, have a photo ID and your confirmation number and they will check in FOR you...so you'll likely get that A section!!!
