Improve error message

src/moapplication.cpp

@@ -393,7 +393,7 @@ void MOApplication::externalMessage(const QString& message)
     if (InstanceManager::singleton().currentInstance()->gamePlugin() == nullptr) {
       // This can happen if MO2 is started with the --pick option and no instance has
       // been selected yet, in which case m_core will be null.
-      reportError(tr("No instance has been selected. Cannot download mod."));
+      reportError(tr("You need to select an instance before trying to download mods."));
     } else {
       MessageDialog::showMessage(tr("Download started"), qApp->activeWindow(), false);
       m_core->downloadRequestedNXM(message);