How to create an interactive SVG with hotspots or object data

Hi,

I want to create an interactive SVG file with Corel Designer.
What I want:
1 The user should press a red circle.
2 Then this red circle should change its size (or something like this) for some seconds.
3 Additionally another square should start blinking with a certain frequency.
4 When the user clicks on another circle, the blinking should stop.

Possibly step 2 (red circle changes its size) can be achieved with a hotspot although I am not sure. When I experimented with hotspots, then I got an error message when I tried to open the SVG with my Firefox browser.
XML processing error: mismatched tag. Expected: </defs>.
Address: file:///C:/Users/Documents/signalling_interactive.svg
Line 227, column 6: </g>

Step 3 and 4 might be achieved with object data.
However, I do not know, how to do this.
The online help is very vague. And I also did not find anything specific in the internet or any forums.
Did anyone do something like this?
Can anyone help?

Best regards

Winfrieder