Every theme has a particular template that is used to publish the front page of your site. You can change the page that is displayed by following these steps.
First, click on "Site" in Koken's main navigation. The left column (see below) will display each of the navigation groups your current theme displays. The link with "front" next to its title is the first page a site visitor currently sees.
In order for a different page to be front it needs a link in the navigation group. If you don't already have that link, click "Add links" then add the link you want to use for the front page. Please note that only internal links may be assigned as your front page, not custom links to outside sites.
With your new front link ready, mouseover its title in the left column. A gear icon will appear at right (see below). Click the gear, then choose "Assign as front page" from the pop-out menu (see below).
If you'd then prefer to remove the link from your navigation but retain it as the front page, you can do that by clicking the gear icon again next to your newly assigned front page and selecting the "Hide link" option, as shown below.
If you'd like to remove the link that was formerly used as the front page, click its gear button and select "Delete link", as shown below.
When finished click the "Publish changes" button at bottom right to make your changes live.
That's it! You just made a different page the front page of your site.