The first piece of info start with `gg`, so it is easy to come up with `discord.gg` (in fact this contest is held in discord). And then, we use a random discord server invite link, and change the latter part of the url to the first piece of info, we entered a discord server called `sdctf admin chat`.
After entering the discord server, we can see a lot of flag with format `sdctf{m@st3R_h@Ck3R_XXXX}` in `flag-chat`, and we guess that the flag is among it. Therefore, we have to locate the position of the correct flag.
Then we noticed the second piece of info, and notice that we are current in
https://discord.com/channels/810237829564727308/810237829564727312
and the second number in the url is the first number in the second piece of info, so we guess that we need to add the second number to locate the position of the correct flag.
As a matter of fact, if we choose one of the flags, e.g., `sdctf{m@st3R_h@Ck3R_9986}`, click `...→copy link` on the right, and paste it into notepad, we can see that the link is like the following:
> https://discord.com/channels/810237829564727308/810237829564727312/810382719396610111
So we just need to replace the third number in the url to the second number in the second piece of info:
https://discord.com/channels/810237829564727308/810237829564727312/810359639975526490
And we find the correct flag. The correct flag is:
```sdctf{m@st3R_h@Ck3R_4807}```