All Kadence Themes have the same initial setup and install. To view these steps, head over here. Then when complete head back here for your theme specific tutorials.
IMPORTANT Color Pallet Notes
The Rosette theme has custom code that adds a hover color to images. Because you can not adjust this directly in your editor we have tied it to the #1 spot in your color pallette.
Change Menu to Single
To modify the menu to be a single row below the logo you will follow these steps.
STEP 1: Go to Appearance > Menus and create a new single menu since you will only have 1 menu now instead of 2 displayed. Then assign that menu to your Primary and Mobile locations.
STEP 2: Go Appearance > Customizer > Header > Remove the secondary menu from the the right of the logo location. And then place the Primary menu centered in the bottom row.
STEP 3: Click on Sticky Header that is in the left panel. Then click on Enable Sticky Header and choose what will stay sticky. You can modify it to be the entire header, or only your bottom row.
STEP 4: Click the Design Tab in that same window and you can modify what color it will be when sticky as well as other design settings.
Change Grid Images
The Rosette Grid Images are background images. To change them you would click on the block and then in the editor panel select Background Image and load in a new image. You can also select Fixed and create a scrolling background image for this section.