It is necessary to use Pen tool to make explosion depiction in animation style.
The point is to add colors with the Pen tool every 0,25 seconds.
If you use as many frames as possible, you can export the video smoothly.
Free sound effects
I currently use free sound effects.
There are sites that offer a variety of free sound effects, but be aware that you may need to paste a link when using it.
I feel that paid sound effects are not extremely high quality material sounds than free sound effects.
If you pursue commercial purpose and quality, I think that you can order the desired sound source material on the paid site.
The video below consists of three frames. ↓
WACOM for detailed description
Pen tablets are one of the business tools for animators.
I myself use a WACOM pen tablet.
This product is very powerful and can be purchased relatively cheaply.
By the way, my favorite product is Wacom Intuos.