Bootstrap 4: Use row and grid and create a sidebar
Hi Peter, I vaguely remember if this was the case:
In bootstrap 4 you can use grid and row which internally uses flex, so you don't have to.
For example; in discovery portal I use col-md-X (X being the number of columns) By the way they are using bootstrap 4
https://medium.freecodecamp.org/learn-the-bootstrap-4-grid-system-in-10-minutes-e83bfae115da
Also you can do a sidebar:
https://bootstrapious.com/p/bootstrap-sidebar (Bootstrap 4)