The RER train from Paris CDG airport to Paris Nord is not part of Eurail Pass, but you can buy a ticket to Paris Nord station. From there you can take the Thalys high speed train directly to Amsterdam (you need for this train a reservation and this trains should be in the app).

Thanks a lot Angelo for your reply. Really helpful. Another quick one if you could help me out, is Thalys a part of eurail network as in Will my eurail pass cover it or it’s a different entity altogether .

TLs is the brand-name of superfast TGV-lookalike trains from Par (ev 30 mins) to Brussel-then out to AMS or Germany. There is a hefty SURcharge to use with a pass-equal to the (impossible to get at short notice) lowest promotion fare. TLS is to merge with EuroStar soon.

You CAN avoid going via Paris on RER by using a FRench TGV from station at airport to LILLE (arr station Europe_walk over to Flandres=10 mins or 1 stop by payable tiny metro, the hourly train to Antwerpen (via lovely Gent=a lookalike of Brugge), admire this station=railway cathedral, change to hourly local yellow train to Rotterdam-Amsterdam. Takes longer, brings much more sights. That non-Indian superfast you can do later.

You should in fact be entitled to a free ticket for RER by Qing up-learning FRench, and showing pass at counter, this only works TO Paris and NOT from (as that is metro/RATP and not covered).

Your pass is valid for 4 DAYs and not 4 rides-on a chosen day can do as many traintrips as possible.

BTW-AMSterdam city is currently actively DIScouraging any more tourists to come there (I have worked for them in the past, but for quite other things)

Thank you mcadv for such a detailed notation, Will do my bit Once I reach paris and if need arises I shall rather cancel my eurail pass if that doesn’t help me travel when all am looking for is convenience and comfort. 
but thanks a lot for all your help

Attention, there is no longer a direct train between Lille Flandres and Antwerp, but with 1 change.

Thank you sven for the update 

I am a first time user we are traveling from NZ and wish to travel form Paris to Amsterdam  we do not have a eurail pass as this will be a  one time train ride for us as we are cycling the balance of our time in France  Cheers Graeme Wish  to use the high speed train TGV

Then just buy a normal ticket from SNCF.