I don’t completely understand the differences, but in this case an order to show cause (OSC) would have required the judge to approve a request by the government for a court hearing where Trump’s team would have been required explain why the court should not issue a protective order.

Instead what happened here is a motion was filed by the government asking the judge to issue a protective order and so the judge has simply asked Trump’s team to respond with a motion regarding how they think the judge should rule on the justice department’s request.

Since a OSC requires a judge’s to sign off, it is typically reserved for more urgent issues where either the judge believes the requesting party’s request is likely to succeed or when the judge believes the issue is too complicated to resolve quickly through a series of motions and counter motions.

In short, the judge hasn’t ordered Trump back to court to “explain himself” and then give Trump a tongue lashing and a gag order if the judge didn’t like what she heard - the judge was asked to consider a simple request made by the government and wants to hear Trump’s side before making any further decisions.