FileZilla: https://filezilla-project.org
This lets you exes the Server directory. We will use it to install mods faster (if you only play with 5 mods you don't need to use this program)

1: Let Nitrado (your any third party Hoster) set the server up
2: Start the server
3: Stop the server
4: Install Mods with FileZilla
5: Start the server on Nitrado
6: Open the settings in the web-interface of FS22 and enable the mods (this is also the point where you would upload the mods if you don't use FileZilla)
7: Start a Solo game on the desired Map
8: Save the game and quit
9: Zip your Save file (Located in documents->my games->FS22) and Upload it to the web-interface
10: Set the uploaded Savegame as default in web-interface
11: Start the server in web-interface
12: ignore the Error Message and press F5
13: Ignore the Mods not working do to your friend downloading them from fishy third party sides
14: Play on the server

Optional: cry because the log system of FS22 is the worst ♥♥♥♥ you have ever had to endure because it doesn't help you one bit while the online forums also have not clue on what to do so you are on your own (this step can be done throughout the whole Process)

PS: Try not to play with "Friends" who have a 12GB mod Folder, it will destroy you trust me... i have experience.....