transportation, train

I don't know where Flr is, but Luzern-Strasbourg is easy by train. Strasbourg-Bruges is not that hard, but might require a change in Paris from Gare de l'Est to Gare du Nord. And if Ams means Amsterdam, it is very easy to get there from Bruges.

Does flr mean Florence? It is really hard to understand what you are asking.

Why do you think you need a "euro rail pass/" - you don't. I suggest you do a bit of research on the ManinSeat61 website for very comprehensive information on train travel in Europe.

flr is florence and w i was not sure the trains went from flr to luzern.

Use https://www.bahn.com/en to look at train schedules. You cannot buy tickets here, unless the train begins or ends in Germany, but they have everybody's schedules. Be aware that there are 2 general European wide schedule changes every year, Dec 12 and June 12 for the coming year, and often will not show all the trains after these dates. Just look at nearby dates to see what is possible. The schedules usually don't change much.

Florence to Luzern is 5 1/2 hours with 2 train changes, at Milano Centrale and Arth-Goldau.

Also note that if you have a Eurail Pass, you must buy separate seat reservations for certain legs, like Florence to Milan, Milan to Arth-Goldau, Strasbourg to Paris and Paris to Lille Flandres (on the way to Bruges). Buying advance nonrefundable tickets will be cheaper than a Eurail Pass as when you purchase tickets, the required seat reservations are included in the price.

The whole trip is easy by train, and I would not encourage you to get a Eurail pass because if you have one, you still need reservations for trains in Italy and France. It is more complicated and rarely cheaper than just buying train tickets.

For Strasbourg to Bruges, the most frequent route takes you to Paris Est station, a 10 minute walk to Paris Nord station where you can take the train to Brussels-Midi, and onwards to Bruges.
On most days, to avoid that change of stations in Paris you can also take one of the few direct trains from Strasbourg to Brussels-Midi, then on to Bruges.

Also, please avoid using airport codes to abbreviate city names; not too many people are familiar with them.

As noted by others all of your trip is easily done by rail using individual tickets. You don't mention your arrival/departure cities for US to Europe/Europe to US, or whether the order named is random or done in a particular order. Maybe plot your trip with the actual start in your arrival city and move progressively around your destinations in geographic order. If your first desired stop is Florence then you most likely will be flying/taking a train into Florence from somewhere else (Rome? Milan? Venice?) so that will be your actual starting point in Europe (Milan - Florence - Lucerne - Strasbourg - Bruges - Amsterdam? ). Flying into Italy and out of Amsterdam would work easily with connections to the US.

If you’re referencing FLR the airport, you need to transfer by taxi, bus, or tram to Firenze SMN train station.