Often they would be considered the same but to steer would be used for vehicles with a steering mechanism, and to guide would be used to guide a person or animals to somewhere or to assist in showing the way. You would steer a person in the right direction if they were lost and asking for directions. You would guide a young child to becoming a mature adult over time. You would guide or steer a person to the correct street to find the bus stop. you would guide an old person across/over a busy road. You would steer a vehicle car/ bicycle etc. You would guide a horse or animals to somewhere. Steer may be used to show someone the way to a location but guide or show them to is most common.