Layout is done automatically, but you'll get to choose style.
The one being shown here is "Grid" where your party is shown top to bottom at the right while enemies are shown on a grid at the left like FF1~FF3. It measures the box of each enemy sprite/image and arranges them in a loose grid.
There are two parameters, top and bottom that define the standing area of the map and there will be a parameter for perspective tilt. The perspective parameter is ignored by the Grid layout. It also doesn't obey surprise, surrounded, and pincer situations.
You can also see the numbers at the top left, a common parallel event, continuing to run like nothing happened and generating GUI elements on top of the battle.