Is there anyone who can help me set up my server?
I'm very lost on that.
Have a 3GB 4 slot Nitrado server.
Can someone explain to me how I do all the modes e.g. BedWars, KBFFA, SkyWars, LuckyBlockwars etc.
You need software that supports plugins (Paper, Tuinity or Purpur).
And then you look for the game mode on the Internet (e.g. "BedWars Plugin") and go to the plugin's spigot page.
The plugins are then placed in the "plugins" folder. Then you need to set up the games. Either it is explained on the Spigot page or on YouTube.
You will need developers and more than just a 4 slot 3GB server. So many modes also need a lot of RAM and cores. Also, a V-Server / Rootserver / Dedicated Server is better if you want to make this thing public