The actuators can be divided into single and double-acting, the former have one supply and the return is made by a spring and we use 3/2 function valves for them. The 5/2, 5/3 valve functions are used for double-acting cylinders, i.e. those that need power to extend and return. First of all, please determine the type of actuator control, mechanical or pneumatic or electrical. Then it is necessary to select the function, i.e. whether the actuator should stay in a given position or hide after the control disappears (mono or bi-stable). The size of the connection threads is selected according to the size of each actuator. I encourage you to contact the customer service department to arrange the details.