The author of the guide linked to by OP has a series of docs for resetting the 6610 to factory settings and licensing all the ports. My understanding is that especially for the old switches like the 6610, it’s not possible to buy licenses anymore so you can just unlock them.

For copper 10gbe connections, you have two main choices: you can use DAC cables which end up being cheap but are hard or impossible to fish through walls or terminate at a patch panel, or you can use a 10G-BASET transceiver which gives you standard RJ45 jack but costs about $50 for each end of the connection plus the cost of a cat6 or better cable.

Edit: obviously if you already have a device with a copper 10gbit port, then you only need one transceiver (for the switch port), and using a DAC is a no-go since DACs require SFP ports at both ends of the connection.