If you can't quite remember something flexbox related, this compact 1 page visual representation might help. Scan through the thumbnails for the desired example. If looking for more than a cheatsheet, try MDN's "Using CSS flexible boxes" or Philip Walton's Solved by Flexbox.
Parent Element
All Positioning
1
2
flex-direction
justify-content
f
n
o
align-items
Multiple Lines
1
2
3
flex-wrap
align-content
Children Elements
Full Bleed
✗
flex-grow
default: 0
✗
flex-shrink
default: 1
flex-basis
default: auto