You should be able to Open a Brokerage Link account on the NetBenefits website. I tend to find it easier to do certain tasks on a Desktop versus an iPad.
Once the Brokerage Link is open, you should be able to transfer funds directly to it. Don't know if there's a Transfer In Kind option or not if you wish to simply retain some of the funds. Notably Primecap. Primecap is closed except for legacy options.
But sounds more like you want to branch out to different investments or stocks.
Only limitation I'm aware of with the Brokerage Link option is that you can't buy FedEx stock, should you choose to do so.