Help with Homepage

@redappleeducation: thanks for your question but you should have posted in your site URL so that I could check in live. Next time please ask question specific to your site URL.

Now, I assumed that you are using Catch Kathmandu Free theme and you can check out the theme instruction page first at http://catchthemes.com/theme-instructions/catch-kathmandu/

1. I cannot change the graphic on the homepage?
— There are 3 elements in Homepage of Catch Kathmandu and further you can also enable latest post or static page under it.
1.1 Featured Slider:
* First, you need to create post from “Posts => Add New” and add in the Featured image in your post.
How to add Featured Image in Post?
* Open the editor of the post where you want to display image, and locate the Featured Image module in the bottom right corner under Page Attributes. Click on Choose a Featured Image.
* Then you can either upload the image from your computer or select the existing image from your media library and click on Set Featured Image. Click to view screenshot
* Then you need to go to “Appearance => Theme Options => Featured Slider” and in Slider Options, select Post Slider or Category Slider.
* If you choose “Post slider” then you need to go to “Appearance => Theme Options => Featured Slider => Featured Post Slider Options” and simply insert the ID numbers for Posts in the boxes, one Post ID number in each box. Click to view screenshot
But if you choose “Category Slider”, then you need to go to “Appearance => Theme Options => Featured Slider => Featured Category Slider Options” and select the category.
* Click on Save Changes button
But if you want Featured Image Slider where you want independent image slide then you need to upgrade to Pro version. See the Catch Kathmandu Pro version theme instructions at http://catchthemes.com/theme-instructions/catch-kathmandu-pro/

1.2 For Homepage Headline
This headline comes with default text. You have the option of changing headline and sub-headline text or disabling it through “Appearance => Theme Options => Homepage Settings => Homepage Headline Options” in your WordPress Dashboard.

1.3 For Homepage Featured Content
Homepage Featured Content Options give you the ability to showcase your portfolio, photos, articles or services in Homepage. By default, this featured content is shown with default images and texts. You can either change the image and text or disable it through “Appearance => Theme Options => Homepage Settings => Homepage Featured Content Options” in your WordPress Dashboard.

1.4 Enable Latest post or static page
* Go to “Appearance => Theme Options => Homepage Settings => Homepage / Frontpage Settings” in your WordPress Dashboard
* Next to “Enable Latest Post or Page?”, check the box that says “Check to Enable” and save changes.

2. is there a way that I can reduce the height of the header?
— For this, I need your site URL. But I am just generalizing that you are using default settings. You can adjust the padding as per your need and add the following css in “Appearance => Theme Options => Custom CSS” box.

#site-logo, #hgroup { padding-top: 20px; }
#hgroup-wrap { adding-bottom: 20px; }

3. Finally, how do I change font of the titles in the menus (homepage).
— You don’t have font option in Free version, you need to upgrade to pro version. You can add web-fonts css in “Appearance => Theme Options => Custom CSS” box.
#masthead .menu { font-family: sans-serif,Arial; }