Do you have any tips for what I should do now, what to prepare in advance towards the trip?
Know your product the best you can.
I have no idea what it is, and you may not want (or be able) to tell us, but lets say it is function generator with an LCD used interface and keypad.
Know your way around the menus on the screen.
If some of them are a bit obscure and hard to memorise, make a "cheat sheet" or "Noddy Guide".
If you are taking schematics or user manuals with you, familiarise yourself with them so that if you have to go looking through them for whatever reason you can go to the right area with the minimum of fuss.
Know what all the connectors do, know where to find the specs of the signals in and out of the connectors.
Know what any knobs and switches do.
When you are there, be aware and guard your stuff.
If you have a laptop computer with you, make sure that it is locked so that no one can can steal the software/data from it while you are at lunch.
This sort of thing is probably more likely in "non Western" cultures than USA or Europe.
Don't allow yourself to be bullied into giving stuff away.
People may ask for information or software which your company does not want to give away.
Just say "No, I cannot give you that, I am not authorised to do so"
or "Sorry, it is licenced software, I cannot give it away.
If necessary tell them to speak to your boss back at base, that will usually shut them up.
All these are usually guaranteed to turn the cheeky smiling face of a freeloader into the look of a kid who has lost his bag of sweeties!
Anything else?
JimB