Problem with list numbering

[Marcia]

Hi, this is related to my earlier post asking help in list numbering for which Stefan Blom promptly directed me to Shaun Kelly's. I applied Shaun Kelly's A to Z instructions in an existing list. I think I got my list numbering right in levels 6 up to level 8 but something is wrong with levels 1 to 5. I had been trawling the web for days but I couldn't find what I am looking for. My list numbering is like this:
Level 1 - 6


Level 2 - 6.1
Level 3 - 61.1
Level 4 - 611.1
Level 5 - 6111.1
with the cursor at the end of the text of level 2, when I hit enter, there should be a number 6.2 but it showed a blank line. Also, there is a triangle mark beside levels 1 to 5 and I don't know what it signifies. Please point me to where I went wrong in the list numbering. Thank you.