First time flying Asiana into LAX and then connect with United back to DFW. I will be checking bags. Please advise:

1. After landing, do I need to collect my bags at TBIT?

2. Do I need to get out of the terminal and re-enter UA's terminal (I don't know which of the Terminal 6,7,8 does my flight leaving)

3. Are Terminal 6,7,8 connect to each other post-security?


Thanks in advance!