Update templates

This extension uses fluid templates so you are able to override them like in most other TYPO3 extensions.

Override template using TypoScript

Do you have a site package? Put the templates into your site package extension. Otherwise you can put them into fileadmin if you really want.

plugin.tx_reserve {
        view {
                templateRootPaths >
                templateRootPaths {
                        0 = EXT:reserve/Resources/Private/Templates/
                        1 = EXT:site_package/Resources/Private/Extensions/reserve/Templates/
                }
                partialRootPaths >
                partialRootPaths {
                        0 = EXT:reserve/Resources/Private/Partials/
                        1 = EXT:site_package/Resources/Private/Extensions/reserve/Partials/
                }
                layoutRootPaths >
                layoutRootPaths {
                        0 = EXT:reserve/Resources/Private/Layouts/
                        1 = EXT:site_package/Resources/Private/Extensions/reserve/Layouts/
                }
        }
}

Override template using constant editor

TYPO3 Backend > Templates > Constant Editor

Constant editor