The first thing to do is to coop and run train them. Don’t let them sleep in the trees (unless you want a semi-feral flock).
Lock them up in the coop for several days so they are forced to use the roosts in the coop. If you have older hens, you could maybe selectively let those out but keep the Game pullets cooped up.
Randy might do randy things with them! After you have coop/run-trained these pullets allow a few weeks to pass after they start laying. Collect their first eggs, which will be small, for sure.
Later, once their egg size is relatively constant, you could get a little lazy about collecting the eggs. They are likely to go broody. Games are ideal broody hens because they are lighter in weight than other broody breeds and are less likely to break eggs. They are also very good mothers to baby chicks.
They can raise some baby chicks for you, with no electricity cost for incubator or brooder! They love to do that!
Note that broody-raised chicks are a little more wild and skittish than incubator-brooder-raised chicks. These were likely raised by a broody hen, so they need a bit of tough love in the cooping-up department.