Tube Fire What Next?

I have a melody el34 integrated amp. I truthfully don’t know much about how to maintain it. About a year ago I had a well respected tech do some work on it and put in new tubes. Last night the family was listening to music and it looked like there was fire inside of one of the power tubes. Scared the crap out of my daughter. I turned off the power and unplugged it.  I assume I need to replace the tube. Is there anything else I should do? I have never biased the amp myself but I did just buy a multimeter which ironically just came this week. Can someone walk me through this so I don’t bust my amp or more tubes. Thanks for the help.