I know how to render the animation playing, but can't figure out how to just render a burst only. Is this possible, and if so please advise how I can do it.

For that you need to set the delay start in particles close to finish.

I will do some tutorial about it due is some tricky!

Here is a tutorial that how create a explosion, that is just a burst if is what you want to do:

Thank you very much for the tutorial @Kronbits :D

(I hope in next ones you also add a voice over, or/and subtitles, or at lease some kind of "click feedback" so we can follow the tutorials easier, anyway good job)