Solid state relays come in all varieties of switching device. You can get them with bipolar, FET, Triac, SCR, and combinations to produce whatever desired switching ability you need. Some provide automatic zero-crossing turn-on, or other states of switching, some merely turn on whenever the control signal is applied.
You would need to decide how the load needs to be switched. Is it AC, does it need to be switched on at the zero crossing? If it is purely a resistive load, and DC, your choices of components is different.
Any of the makers of these devices will give examples of what driving circuit is reccomended, and if any extra circuitry is needed on the load side ( snubbers, etc )
Switching a solid state relay on and off is very simple, you only need to pick the right one for the job, and operate it within its designed characteristics.
Without knowing what load and power/control source you have, reccomending any device is not possible.