Hello new to growing Grapes. Quick Question!

[Walkerkc88]

We bought this grape vine (Reliance) from a local greenhouse. We just planted it and we live in Iowa.

Should we prune one of the main stems now or let them both grow the first year and prune in the spring. (photo attached)

Thank You,
Casey

 

[Rice_Guy]

Year one I establish roots and let the stalk build energy
year two i shape one (sometimes two) trunks
year three I shape cordons on the trellis wire

grapes are weedsa;d hard really hurt them

 

[Walkerkc88]

Year one I establish roots and let the stalk build energy
year two i shape one (sometimes two) trunks
year three I shape cordons on the trellis wire

grapes are weedsa;d hard really hurt them

Thank You!