You only need a reservation for the TGV from Paris to Lyon.

You can book it online here:

https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish

(currently €10 per person plus €4 per order)

You'll need to give a pass cover number, which is on the pass cover of the paper pass cover or which you can generate if you have a mobile pass.

You can also call SNCF. Press #85 for English, no booking fee, reservation is sent via email.

Thanks so much.  I am trying to book a train from Paris Gare de Lyon to Bellegarde on May 17. Can you help with that?  I see that it is available but can’t figure out how to do it

All direct TGVs are fully booked for that day (keep in mind that this is the day before Ascension day so it will be very busy). Which train (departure time) are you trying to book and where do you see it's available?

Rail Europe

I just realized it is Paris to Chamonix Mont Blanc which is actually fine

Departs at 14:59 from Paris Lyon to Paris Lyon Part Dieu

44 min chage

to 

Autocar #39757

17:40 Lyon Part Dieu

21:40 Chamonix Mont Blanc

and Rail Europe has one that leaves at 6:24am from Paris Lyon to Lyon Part Dieu

change of 16 minutes

TER #96504

8:38 Lyon Part Dieu

10:06 Bellegarde

My ultimate goal was to get to Chamonix but thought it was easier to go to Bellegarde and take a car from there to Chamonix - didn’t realize I could get there with just one change

To book the TGV Paris - Lyon, please see my first reply. If that doesn't work for you, then please explain where you get stuck. A screenshot would also be helpful.

Reservations are not available for the bus (autocar) Lyon - Chamonix. Just add it to your pass shortly before boarding.

when I go to that website and I put in Paris de gare which it takes, I can’t get it to take Lyon or Chamonix on the “to”.  And where/when would I put in the pass number.  I can’t thank you enough for trying to help me

can we just add the passes to this rail europe ticket?

You need to enter Lyon as your destination. Your screenshot shows you trying to enter Paris as the destination. Don't enter Chamonix, since you can't book a reservation to Chamonix.

It will ask for your pass cover number in a later booking step. It's a booking page specifically for pass reservations so you'll see the correct price, provided you've selected the correct pass.

The Rail Europe website can't book pass reservations.

I can’t thank you enough for all your help.  Finally got these tickets purchased this morning.  I would not have been able to do this without you.  Where are you located?  It was the middle of the night in Europe!

I'm in Belgium :)

Someone doesn’t sleep much -