Hey Vondo, I have a bit of experience with growing in greenhouses myself.
For temperature control, I find that good ventilation is key. Open windows and doors to let hot air out and cool air in. If you want to make it even easier, automatic vent openers can do the job for you. To keep things cooler inside, you can use shade cloths to reduce the amount of sunlight coming in. This helps prevent the greenhouse from overheating, especially during hot summer days.
In colder months, I find that small heaters or heat mats help in my greenhouse, and even some water barrels can help by absorbing heat during the day and releasing it at night.
For humidity control, proper watering practices are essential. Water your plants in the morning to give the moisture a chance to evaporate during the day, and avoid overwatering to prevent excess humidity. Good ventilation also plays a role here; keeping vents open helps reduce humidity by letting moist air escape and bringing in fresh air.
Hope this is helpful!