Minecraft Bukkit 1.14 Gamemode, Admin?

I have a question about Minecraft Bukkit Server. I have one that runs over Nitrado. Unfortunately, I do not understand how I can set admins myself, or in which file I have to do that. Because if I want to execute ingame certain commands, I get the message that I have no permission, of course.

Then to Gamemode, do I have to install these commands to install some plugin? Because if I enter this, I get the message that these commands do not exist.

/ op [name] in the web console, done.

Manually entering the date is somewhat more complicated.

The game mode command has been redesigned and now reads "/ gamemode spectator / creative / survival / adventure" (each one of the four)

You mean the "op.txt" file, right? I even trust children to edit these. That's not complicated at all.

The op.txt has since been replaced by the ops.json, which, however, has become much more complex due to the need for UUID etc. I did not want to take the questioner by surprise, even if it is much easier.

You're right.
I have not been actively playing Minecraft for 5 years, back then it was still a text file.

In the Nitrado Web console you do not have to type "/", because everything you enter is interpreted directly as a command. In any case, I believe - that's how it used to be ^^

For some reason that did not work with the op.txt file. In the console I only had to enter "op Name", without /. That was my mistake all the time.

There you are right again, the Slash got lost. In the game it would be "/ op [name]", in the web console of course "op [name]" Thanks for the tip!