train paris to brussels to bruge.

If you miss the connection your ticket is good for the next train.
What time do you arrive in Brussels and what time do you depart for Bruges?

Even if you have a premium product train from Paris, most of the continuations to Brugge are on very frequent (six or more per hour, during business hours) local trains. It is unimportant whether you make the expected connection or not. In fact, Brussels Midi/Zuid is a very simple station. Able-bodied passengers with no luggage should be able to make the transfer in less than five minutes. Even if you have to walk to the elevator at one end of the platform and wait for it, ten minutes is a very generous allowance.

On your return (?), note that the train from Brugge stops in three downtown stations, Bruxelles Nord, B. Centrale, and B. Midi/Zuid. (They are all in the same fare zone.) Some trains to Paris stop ONLY at Midi/Zuid. I don't mean to complicate matters for you, but there are a few trains to Paris from Antwerp as well.

Belgian internal trains do not have reservations, your ticket is valid for any train from Brussels to Brugge that day.
So spend a few hours in Brusels if you want.

It should take less than 5 minutes to get between any two platforms.

Note 1: there are three stations in central Brussels: Bruxelles-Midi/Brussel-Zuid (the main one), central and Nord.
Plan of Brussels Midi: https://static.b-europe.com/-/media/MediaRepository/Files/Station_Plans/BEBMI/MAP_Brussels-Midi_EN

Note 2: Brussels is officially bi-lingual, so all train listings are shown in both French and Flemish: Brugge/Bruges. You train will be listed by its end destination: Oostende/Ostende (English Ostend). Once in Brugge, it is Flemish only.

I did this in April. My Thalys train was about a half hour late leaving Paris. I missed the connection (because I did make a comfort stop too). I just hopped on the next train (actually to Gent/Ghent not Bruges but the same applies) as Chris suggests. The conductor was very nice and joked (in perfect English) that I was taking the scenic route as that particular train was a few minutes longer than the one I was originally booked on. He chatted a few minutes more and moved on. Extremely easy and the experience was quite pleasant.

Do not spend any time worrying about this.

If you take a taxi from your hotel in Paris to the train station give yourselves more time than you think you’ll need. I was totally stressed because the traffic was so bad around Gare du Nord. I thought I was going to have to bail out of the taxi and walk the last 2 blocks but the driver wiggled thru. (Yes, I gave him an American tip). Fortunately the train WAS late!