You will find the password to unzip either in the tutorial section or by reading the description of the download.
Please make sure that you first exclude all possible sources of error (incorrect settings, foreign mods, etc.) as best you can.
Check whether your problem can be found in the FAQs or whether it has already been dealt with in the forum using the forum search.
If you cannot find a solution to your problem, please ask your question clearly and with the attached log.txt - no one else can help without log.txt.
For Farming Simulator:
The log.txt is automatically generated by the game at each start.
You can find the log.txt under
PC: ...\documents\my games\FarmingSimulator2019
MAC: ~/Library/Containers/com.astragon.farmingsim201X/Data/Library/Application Support/FarmingSimulator2019