How to edit { CONTENT } in Forumotion templates? [LOCK/DELETE]

Hi there!
I looked through the forumotion HTML templates and I'm constantly seeing these:

EG. {catrow.forumrow.avatar.LAST_POST_AVATAR}
{switch_user_login_form_footer.switch_fb_connect.L_OR}
{catrow.forumrow.LAST_POST}

How do I edit those? Through CSS, JS? And what do I type in when I want to edit them?
In this case, I'd like to change the border-radius of the profile pictures to make the edges sharp and maybe add a border to them. I really need this for future purposes also!

Thank you very much!

Those are the codes that make things work. 

Example:  {catrow.forumrow.avatar.LAST_POST_AVATAR} is for the avatars to appear in the last post column on the homepage.

What exactly do you want to modify?

I would like the profile pictures to be sharp edged and have a white border of 1px.

That would fall under CSS.

It would look SOMETHING like this.

Code:

span.postdetails.poster-profile img {
  border: 1px solid;
  border-color: #FFF;
}

Thank you ✰, nothing has changed though.
My forum version is phpBB2, maybe that's the problem?

Is this your current forum?

I tailored to code specifically to your site. Try this:

Code:

span.postdetails.poster-profile img {
  border: 1px solid;
  border-color: #000;
}

See if it gives you a BLACK border.

Be sure to add the code above into your CSS and not in template. 
Admin panel -> Colors -> CSS Stylesheet

Thank you all for suggestions but I figured out the problem myself!
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