Let them grow all summer so some of their energy will go into making a stronger root system. They can be cut down once they die back in the fall/winter. Some people corral them in by putting stakes around the edge of the bed and tying string around the perimeter. But it shouldn't hurt them if you want to let them flop.

Yes, the ferns can often blow over especially when the crowns are young and the ferns are thin. What works for me is to put rebar stakes in the corners of the bed and then wrap twine between the stakes to provide support for the ferns. You can add as many stakes as you want and run the twine between any 2 stakes. You don't want to drive any stakes near where the crowns are growing because that would damage or even kill the crowns.

You will wait to cut them back in the fall after the ferns have browned down. I usually do it around Thanksgiving. Sometimes individual ferns will die and brown during the summer and you can remove those if you want. Be sure to fertilize 3-4 times throughout the year and water the area deeply every couple weeks to keep the plants healthy.

ETA: Ravinhair and I were typing at the same time...good advice!!

I am also on year 2 and did pretty much what LoneJack and ravnhair are suggesting with the majority of mine just because I kept feeling the need to get them to stand up but that was purely aesthetics. It was making me twitchy. :)

Many thanks to all for the great advice