Joomla 4 has changed the float options for images: there is no select box with "right", "left" or "none" anymore, but a field to insert a css class. Nature offer the classes "left" for positioning the full image on the left and "right" for positioning the full image on the right.

Example "left"

Example "right"

You can use the classes globally for all articles, go to Content -> Options -> Editing Layout and enter the class you want in the field "Full Text Image Class".

Or you can use the classes on each individual article:

Screenshot image class

Nature has some other helper classes:

.grid

.grid {
    display: grid;
    grid-auto-flow: row;
    grid-template-columns: 1fr;
    grid-gap: var(--s2);
}

that works in combination with .columns-2, .columns-3 or .columns-4 (they work at a width of 800px, below this point the grid changes to 1 column)

.columns-2 {
  grid-template-columns:1fr 1fr
 }
 .columns-3 {
  grid-template-columns:1fr 1fr 1fr
 }
 .columns-4 {
  grid-template-columns:1fr 1fr 1fr 1fr
 }

The classes are in use in the template, for example to control the layout of the category blog or some modules. You can also use the classes inside your content:

<div class="grid columns-4">
<div class="grid columns-3">
<div class="grid columns-2">