As a rule, you convert the basic layout and the individual areas (Areas) to a fluid-width layout, and center the contents in Joomla over the final modules. Simply enter a .container in the respective module in the module class suffix. Especially in the JW template, areas 1, 2 and 3 should also be left on containers in a fluid-width layout, if you do not want to have this displayed across the entire width.
In the tab Layout the basic settings for the layout can be made:
For a centered layout please select container and for a "full-width" or flexible layout container fluid.
If you do not want any page spacing in the container fluid (bootstrap elements are generally spaced) then select Edge-2-Edge Layout.
Please also note the settings for the following areas 1-26, here also separate settings for the individual areas can be configured.