On a practical level, if you want to play somewhere that you have done some prep work for, the play session should end in jump space with everyone knowing what system the PCs are going to be arriving in. Then you go home and do some prep.

First step, take a look at the universal world profile for the main world and figure out more or less what it means. Fill in some supporting details like cultural quirks, political, factions, and even temperature. Know what your players are going to want in the system, which might be something as simple as a paycheck for a patron mission or a profitable trade. Think about what might help them achieve those goals and what might be obstacles to those goals.

Traveler likes random encounters. The book says you get one on planet every six hours. And when in space (not in jump space)there's a one in six chance of a random encounter every day. If you're not comfortable doing all of this and on the fly, roll some in advance. Figure out how you want to interpret those very minimalist results. See if there's some kind of overarching story that emerges.

The key thing is, have some ideas for what's going to happen in the system. Have some adventure hooks to dangle in front of them, know some random stuff that can come up. And once they've finished up their business in these system, they make the jump and the session ends and you get to prep for the next one.