How can I get Google from interfering with my use of Firefox as my default search engine.

Hello,

Doing so while preserving the look of the new tab requires CSS modifiation. Note : only do this if you know what you are doing.

first, type about:support in the address bar, then next to profile folder, open the folder. (show in finder for Mac). Next, create a new folder called chrome (if your profile folder doesn't already have it), and inside the chome folder, create a .txt file and name it userContent.css, and then paste the following code : Note : to use the userContent.css, enable toolkit.legacyUserProfileCustomizations.stylesheets to true in about:config. CSS code :

@-moz-document url(about:newtab) {

 #newtab-search-container, #newtab-search-logo { 
   display: none !important; 
 }

}

After that, save it, and restart Firefox.

How can I get Google from interfering with my use of Firefox as my default search engine. I just having trouble finding the three buttons, under the Firefox app opening screen. What should I do?

Firefox is a web browser and not a search engine. A search engine is for example duckduckgo.com, google.com, bing.com etc.

Since you posted this in desktop Firefox section see https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox

Your last sentence makes one think you are using the Firefox for iOS/iPadOS version as you used to post this thread with.

In that case see https://support.mozilla.org/en-US/kb/enable-or-disable-search-engines-firefox-ios and https://support.mozilla.org/en-US/kb/change-your-default-search-engine-firefox-ios