Modify my spoiler and auto-open it

Hi guys, I'm editting my forum.
And I want to ask about the spoiler.

I don't know where I can edit the spoiler (size, image, shape). And I really need the spoiler auto-opened.
Please help me. Thank you.

Hi there,

Can you please provide the link to your forum? Thanks.

So you want all spoilers to be opened by default in your forum? Try this Javascript:
AP  Modules  HTML & Javascript  Javascript codes management  Add a Javascript Code

Code:

$(function(){
  $('.spoiler_content').each(function(){ $(this).addClass("hidden"); });
});

Name: Auto-opened Spoilers
Placement: In all the pages

I don't know where I can edit the spoiler (size, image, shape)

You will have to edit the CSS, it would be better if you provide an example on how you want the spoiler to look like.

hello 

read this tutorial 
https://help.forumotion.com/t135638-personalize-the-titles-of-quote-spoiler-and-code?highlight=Personalize