Arduino wood dehumidifier electronic

the project is to create the device which will have one 16x2 lcd, 3 or 4 keys, 3 relays, 1 dht11 temperature and humidity sensor and that device is going to be placed in dehumidifier facility for dehumiding wooden materials. when device is turned on it is neccesery to set the desired value for humidty. as well as desired value for temperature, for example, if the set humidity is 20% but in the same time reall humidty is above that value, the relay should be turned on, if the humidity drops under 20% then switch of relay, also at the start there shoudl be set desired temperature, eg. if set temperature is 20 degrees and the temp is bellow that switch on relay, when temperature gets to desired value switch of relay, it is important to be able to set the desired values for temp and humidity using keys, of course this is al not so complicated, but there is another part, when machines work and dehumidify the wood, at some moment the humidity will drop to the desired level... if that humidity drops lower than desired level for lets say longer than 10 minutes... for example is humidity is at 19% for more than 10 minutes... then this new value should be set as the new DESIRED level, the new value should owerride initialy set value so any new lower value should owerride previous, if drops to 18 new value is 18... or 17, 16 etc, also this should be corelated with the temperature, as the humidity goes down, new set value should go up. humidity goes down 1%, at the same time new set value for temperature should be +1, previous and +1, this cycle should repeat as long as the humidity reaches 6%, and at that moment everything should switch of, print "process finished" at the display and switch on the third relay, also... it is neccessary to be able to set that variable values... their steps... for example to be able to reconfigure that when humidty goes down it does not set temp higher one whole degree but half degree instead etc. Just to be understand When device start we must set temperature, humidity, time x (when humidity is reached and below seted value in minutes eg. 0,1,2,3,4,5,6,7,8......60), step for temperature rising when hummidity is ok and time is passed eg. (+0.5,+1,+1,5,+2,+2,5,+3.....5), humidity for end of process eg. (4,5,6,7,8,9,10,11.....20).