You need:

TENS wires
2 x pin to banana adaptors
2 x 2" by 2" sponge electrodes (you can get Amrex brand)

Putting it together is really simple. You just plug the wire to the Activadose, put one adaptor on each end of the wire, and then the other end of each adaptor will fit into the sponge electrode pocket.

If you search "transcranial technologies" they have a downloadable document that will tell you how to position the electrodes.

The machine ups the current very very slowly, so it is quite safe. If anything strange starts happening, you just ramp down the current manually.

Best of luck.