1) Go to search engine. I used duckduckgo
2) Type in: how do you remove sod from backyard and press the hourglass icon to search
3) Click on links to watch related videos/read websites that will describe the sod removal process.
3a) You will need to rent a sod cutter to make life much easier. But it's possible to do it all by hand too to save money but it will mean lots of sweaty work.
4) Remove & dispose of sod.
5) Replace dirt and new sod as needed.
6) Water regularly until it takes but follow the directions.
7) Be sure to fertilize sod AFTER it takes and sprouts it's new roots.
Bonus: I did the search work for you, thank me later:
https://duckduckgo.com/?t=ftsa&q=how+do+you+remove+sod+from+backyard&ia=web