Run nmap on exitprocess0 with custom args, output aren't streamed, this web interface work without JS. Make sure you are allowed to scan your target blah, blah, blah
What you can do is within a flag whitelist, that said most of flags are allowed and you can even use bruteforce NSE script. Commands taking too long to run will fail...
Simply click on one of the preset and enter your target (Domain name or IP4 / IPV6) for custom flags specify them with their dashes (e.g : -vv -A -T4)
Sadly, for security reasons commands requiring root (such as OS detection "-O") won't work, this is why the intensive preset isn't as "intenstive" as you would expect ._.
If you never used nmap, first I'm sorry to hear that and secondly I advice you to read this page which list all the options and what they do to use nmap like a pro or read their official book to use nmap like a god
Happy hacking I guess~