How do I make Firefox in Mozilla my default settings

In the device system Settings if you go to Apps › Firefox (or any other browser like Safari per se) there will be a row with the default browser selected — you can just change it there. Or, default apps have a special category in that Settings list under Apps, there's usually a top item called "Default apps" or something similar that you can also use to access that category.

After the lake Ontario disaster by the Mad King, I do not want to use Google or Apple and anything I don’t have to. How do I make Firefox and Mozilla my default settings on my mobile as I’ve already done it on my computer.

To change or install another search engine in the Firefox for Android web browser see https://support.mozilla.org/en-US/kb/manage-my-default-search-engines-firefox-android

To make the Firefox for Android the default web browser on Android see https://support.mozilla.org/en-US/kb/make-firefox-default-browser-android

Mozilla the makers of the Firefox web browsers does not have a search engine site of their own as a search engine is for example qwant.com, duckduckgo.com, bing.com etc..

After the lake Ontario disaster by the Mad King, I do not want to use Google

The Lake Ontario is only wrongly renamed to Lake America on US Google as it is still Lake Ontario for people using Google outside of the US.