We observe something new or that we do not understand - it is a contradiction or an incompletenesses in our starting idea. We create a consistent explanation of our new observations using our previous knowledge. In making the model, we use all our knowledge of nature gained from here on Earth, and assume that it is general for the whole universe We express the model mathematically so that we can deal quantitatively with the observations We test the model by predicting things that we have not observed before, and then observe to see if the predictions are confirmed.
Confirmation gives confidence in the model, but it never proves that the model is true.
The more times predictions are confirmed, the more confidence we have. After publication, everyone can try to repeat what has been done or to show errors that were committed. One person does not generally do all the steps.