Hi, @pmario and @TW_Tones.
In the end, with your instructions, I managed to do it the way I wanted.
I have made some small modifications that basically consist of putting the title first and then the caption, changing the color and putting the caption results in italics.
I put it below in case it is useful to someone.
\define searchResults()
<$set name="resultCount" value="""<$count filter="[all[shadows+tiddlers]search:title,caption{$(searchTiddler)$}]"/>""">
Search Captions only<br>
{{$:/language/Search/Matches}}
</$set>
<$list filter="[all[shadows+tiddlers]search:title,caption{$(searchTiddler)$}] +[sort[caption]]">
<$link to=<<currentTiddler>> ><$view field=title/> <span style="color: blue"> //<$view field=caption/>//</span></$link>
</$list>
\end
<<searchResults>>
We put this code in a tiddler with the title: Custom search title/caption
and with the label: $:/tags/SearchResults
Then we add the fields: caption
with the content Title/Caption
and the source-tiddler
field with the content Caption search
Regards, and thank you very much.