Now, the sign IN is a tricky one because like in English, the sign IN has various uses depending on the situation and context. For example, "In December, we ...," "The book is in the table drawer," and "You in?" ... See! It depends! Halfpenny Pediatric Speech Services asked for the sign IN in reference to preposition/spatial words. Again, there is some variation depending on context, but over all it's as shown below. (It was funnier than I thought creating my own signing picture. I hope you enjoy!)
Now you'll start hearing me refer to your signing hands as dominant and non-dominant hands because depending which hand dominance you are depends on which hand moves where. As you can see, I'm right handed so when I'm teaching my students I would say, "your dominant hand goes into your non-dominant hand (as shown - my left hand is my non-dominant hand). So your non-dominant hand is stationary and your dominant hand moves into your non-dominant hand.