Their are no specific steps to make a simple rocket. But you have to be a little careful while making a replica.
Firstly I go to the wiki page of the rocket to look at its size and then I make changes according to the engines I am using for example, I made it with half the original size. But first it looks very simple
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Then I take a screenshot of the real rocket and keeping it at recent tab I start adding decorative things step by step. So I shift to three apps the game, gallery and the editor consecutively.
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It's time consuming when you are making a detailed one. The most time consuming were those letters. Building the rest of the rocket took me almost 1 hour but making those letters took almost 3 hr.