If not, get a book on concrete. We are not going to be able to tell you every one of the hundred or so details.
Basically, 0. Buy the necessary tools. And learn about cement-working. 1. Dig and form it. Plan for 4" to 5" thickness. Use a transit or levels. Prepare expansion joints. 2. Install reinforcement metal. 3. Measure and calculate how many yards of cement are needed. 4. Order cement & wait for delivery on a nice day. 5. Pour in cement and screet the cement to proper level. Place expansion joints at appropriate places. 6. Float to get right amount of cream to the surface. 7. Tap on the forms. 8. Finish with broom. 9. Edge. 10. Remove forms and water. 11. Let cure for 30 days, then may use sealer to keep it looking new.
You must know when to finish cement, and get the job done before it hardens. You may want a smooth finish, but it could be slippery when wet.
36" x 36" x 36" = 1 yead of cement. Do the math 36x36x36=? You want a 16' x 16' patio. Do the math, 196" x 196" x 4" = the volume of your patio. Figure out how many yards you will need.
Make sure to have helpers around when the cement arrives. May have to wheelbarrow it to your patio location? You want help with this size of pour.
Its not too complicated, but it is a lot of hard work. Enjoy!