In order to process an orthomosaic image do I need to go through all of the steps 1, 2, 3. All I care to get is the orthomosaic that I can overlay into google earth.
Yes. You need to go through all the steps
If you only want the orthomosaic, you don’t need to do the step 2, however it is recommended to include the step 2 since it would affect the accuracy of your orthomosaic.