I myself struggle with the best way to help, there are so many organizations dealing with refugees but it's impossible to know which ones are legit.
I put up Ukrainian flags on my house, I speak to people and confirm that this is indeed real, I think for now, the best we can do is expressing unity against the war.
In two generations we always forget and unlearn the horrors of war, maybe it will be over soon and life can slowly go back to normal in Europe.