Hi, you all.  I'm new to this community channel 
but excited to share, and initially, hopefully get some help! 
I've got what I think is a tricky question for ya all

My FileMaker app has an unfiltered portal with a field I have named "Counter"
(please see image)
 
I wish for this Counter field to somehow number all the rows in my portal 
and be flexible enough that if I insert a row (I hope to find a way to do that, too) then
all the portal row's "Counter" value will increase by one to make room for the newly inserted portal row,
and the opposite, of course, if a portal row is deleted, then all the subsequent numbers will decrease
by 1.
 
Thanks for your advice,
 
JD  Sebastian
Los Angeles

You don't need a field for this. Just insert the Record Number Symbol into the first portal row - see:
http://www.filemaker.com/help/15/fmp/en/index.html#page/FMP_Help/inserting-variables-on-layout.html

Fantastic!  Two years of intensive study and I still have a gazillion things to discover.  Thanks, works great! 

The upside of the record number symbol is that you don't need to define a field.

The downside is that if you want to fit {{recordNumber}} into a skinny space; that is difficult. There are some stupid FileMaker pet tricks you can use to resize it but they break if you touch the field.

So I often use an unstored calc field, defined as get( recordNumber); and place that on the layout.