how do i make it my default design

[exasko]

i create a new style... how can i make it the default one?

[Zachery]

AdminCP > vBulletin Options > Style & Language Settings > Default Style >
Select the default style for your forums. This style will be used for all guests, and any members who have not expressed a style preference in their options, or are attempting to use a style that does not exist or is forbidden.