Update. I have now completed the Tags page, a few small tweaks and it all came together. Firstly on my factfile pages I put the following code into the template:
[[!toLinks? &tagKey=`tags` &items=`[[*tags]]` &target=`36`]]
I created a TV called 'tags' and for every factfile I fill out, I add 5 words (tags) on the template variable.
I then have a Tags Results page (ID 36 as defined above). On this page I have the following:
<h1>[[!dynatagtitle:notempty=`Posts Tagged with "[[!dynatagtitle]]"`:empty=`[[*pagetitle]]`]]</h1>
[[!getResourcesTag?
&parents=`29`
&elementClass=`modSnippet`
&element=`getResources`
&tpl=`Fact_images`
&limit=`0`
&includeTVs=`1`
&tagKey=`tags`
&showHidden=`0`
&hideContainers=`1`
&cache=`1`
]]
[[!+page.nav:notempty=`
[[!+page.nav]]
`]]
The <h1> tags display the title for the results based on the tag that was clicked. It was borrowed from this page:
https://forums.modx.com/thread/70961/need-help-with-taglister-in-a-blog-format-how-do-i-return-add-a-title-to-the-query-page
The getResourcesTag call displays my results with my template design which is a chunk called Fact_images.
I still did not manage to work out how to do a TagCloud. I did also have a taglister code, but it gave a vertical list of all tags associated with the posts, and I could not work out how to convert into a Tagcloud which is what I really wanted.
But what I have got now are factfile pages with tags, when a tag is clicked it takes the viewer to a results page showing a picture and pagetitle for all factfiles with that tag.
If anyone does know how to make the taglister display as a Tag Cloud I would be very interested in knowing how.
DS