Very confused by Ubuntu XFCE & websites

Firefox can‘t launch any websites. And I tried to launch firefox from the terminal to get some error messages but there‘s no usr/bin/firefox. I know there‘s internet connectivity, because ifconfig displays ip addresses. And I also tried to install Brave through a curl command, I get this when I run it from terminal.

[21253:21253:0218/100756.371839:FATAL:sandbox/linux/suid/client/setuid_sandbox_host.cc:166] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I‘m aborting now. You need to make sure that /opt/brave.com/brave/chrome-sandbox is owned by root and has mode 4755.
/usr/bin/brave-browser: line 40: 21253 Trace/breakpoint trap “$HERE/brave” “$@

And here‘s what I get when I run “sudo brave-browser –-no-sandbox“

[21620:21620:0218/101003.962662:ERROR:base/files/file_path_watcher_inotify.cc:922] Failed to read /proc/sys/fs/inotify/max_user_watches
[21620:21620:0218/101003.965465:ERROR:content/app/content_main_runner_impl.cc:432] Failed to initialize cpuinfo
[21619:21619:0218/101003.969212:ERROR:base/files/file_path_watcher_inotify.cc:922] Failed to read /proc/sys/fs/inotify/max_user_watches
[21619:21619:0218/101003.969994:ERROR:content/app/content_main_runner_impl.cc:432] Failed to initialize cpuinfo
[21613:21631:0218/101004.024657:ERROR:base/files/file_path_watcher_inotify.cc:922] Failed to read /proc/sys/fs/inotify/max_user_watches
[21613:21632:0218/101004.024422:ERROR:dbus/bus.cc:405] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
Invalid MIT-MAGIC-COOKIE-1 key[21613:21613:0218/101004.056157:ERROR:ui/ozone/platform/x11/ozone_platform_x11.cc:256] Missing X server or $DISPLAY
[21613:21613:0218/101004.056180:ERROR:ui/aura/env.cc:246] The platform failed to initialize. Exiting.

And also, what, ping doesn‘t come standard on XFCE Ubuntu? Interesting. Thanks for the help.