There are no Eurail trains, the coverage works by train companies and the vast majority of European trains are included.

I guess you looked at the map on the website ? Unfortunately it is very incomplete and doesn't show half the routes possible.

Where are you looking to travel ? Seat reservations cost extra and limit your flexibility in some countries : mainly France, Spain and Italy + some cross-border routes. Some of those routes are really popular and need to be booked well in advance (thinking of Eurostar for example).

Regular tickets wouldn't really help as they also become more expensive closer to travel date.

On the other hand most of the time you can literally decide seconds before boarding which train you'd like to take! Eurail gives you that flexibility.

I'd suggest reading these 2 links first :

https://www.seat61.com/how-to-use-a-eurail-pass.htm

https://www.seat61.com/interrail-and-eurail-reservations.htm

I will be starting in Frankfurt, Germany.  I want to go to Barcelona, Spain, then, to Rome, Italy. After a few days in Rome, I want to go up to Perugia, Italy for the Umbria Jazz Festival. 

I might pick 1 more city - as I have 3 weeks there.  I’m not sure yet.  I thought about Lisbon - maybe in this order -  Start in Frankfort - then to Lisbon -> Barcelona -> Rome -> Perugia.

How can I find these routes on my own?  Is there a specific Eurail type pass I can get to allow me to travel all over - paying a flat rate and go where I want to go?   Is there an App that I can download to help me get where I want to go??

Look up timetables on bahn.com or in the DB Navigator app. Italian and Spanish timetables from 9 June won't be available yet, but you can look at February or March on the same day of the week to get an idea. Only after that, you can count travel days and see what pass would fit best. Also look at a map and try to arrange the cities in a logical order. Frankfurt-Lisbon is quite long.

Lisbon is quite out of the way and connections are quite bad. I’d leave it for another time, maybe when the high-speed railway has opened! Of course if you really wish to go to Portugal it’s doable → have a look at this page (advice valid from Paris) : https://www.seat61.com/Portugal.htm

I’d do the loop via San Sebastian/Vigo and back via Badajoz/Madrid.

Frankfurt - Barcelona is doable in a day but you might prefer to take it slowly using reservation-free regional trains. Also possible to cross the Pyrénées (Latour de Carol). Seat reservations are something to bear in mind in these countries, have a look at the links above.

Barcelona - Rome will take quite some time but it’s a nice journey along the coast : Nice, French Riviera, Cinque Terre,…

Are you flying out of Rome ? After Perugia you could explore Tuscany or further north : plenty of scenic railways in the Alps!

I will be flying home out of Munich on 7-19, after Perugia.

Thanks for all of your help - its still a bit confusing, but you have helped a great deal.

Maybe I’ll take 2 days to go from Frankfurt to Barcelona - stop some place in the middle - have a nice dinner and stay overnight.  I could do the same from Barcelona to Rome - or maybe take the Ferry from Barcelona to Rome.   

Still planning my trip…...