were it mine, I'd add the water, add some plants, wait a couple days, do a couple water tests (to be sure your'e not an extreme ala pH) and then add. WHEN you do, do it VERY VERY slowly, like an hour or more. What I do is float the bag, opening it and adding a small amount of MY water to the bag. Then every 15 minutes/30 minutes, add more. You want to acclimate them by temperature, pH, general hardness, etc. Slowly allows them to adjust. Now, IF you're doing this with really cold temps, I'd hold off until the water is at least 50F. I've seen/heard of issues/loss of fish when lower temps are tried.
(and yeah, I know; others will say NEVER add the bag water to your pond; I like to live dangerously, I guess; never had an issue that way in decades of fish keeping).
So, make sure your water is okay THEN add the fish. Just a couple. Though, in a pond your size, you could easily add 6 fish under 10" no sweat.