Description
You can use {$label} or {$html} placeholders to let the renderer know where where the element label or the element html are positionned according to the error message. They will be replaced accordingly with the right value. The error message will replace the {$error} placeholder. For example: {if $error}<span style="color: red;">{$error}</span>{/if}{$html} will put the error message in red on top of the element html.
If you want all error messages to be output in the main error block, use the {$form.errors} part of the rendered array that collects all raw error messages.
If you want to place all error messages manually, do not specify {$html} nor {$label}.
Groups can have special layouts. With this kind of groups, you have to place the formated error message manually. In this case, use {$form.group.error} where you want the formated error message to appear in the form.