"Soften" ice cream to make ice cream bars
You just need the ice cream to be soft enough to mold.

Your recipe is referring to store-bought ice cream that tends to be very hard. A little time on the counter will soften it a bit without melting it completely.

A microwave is right out. It would melt pockets completely which would solidify to icy chunks.

If you are making the ice cream yourself then your situation is simpler. Homemade ice cream is still fairly soft when churning is finished. It has to be frozen solid in the freezer. 

Just churn completely and mold.