Hi Cristian
On the page vessel-list you have inserted a View ("Vessel List View") which is set to show both Vessel posts and a Slides repeatable field group. It includes a filter to show posts which are related to the post where this View is shown.
The View is shown on the vessel-list page, and none of your Vessel posts or RFGs are related to the vessel-list page.
How you add a slider depends on whether you have repeating image fields on your Vessel posts, or whether you have images stored in repeatable field groups.
Looking at your site you seem to have mixed the two, because you have a Slide repeatable field group (so you can add multiple slides to a Vessel post), but your slides contain a repeating image field (so you have multiple images in a single slide).
The thread you linked to was written before support for Repeatable Field Groups was added, and is specifically for the case where you add a repeating image field to a post, i.e. you have an image field assigned to Vessels and can add multiple images to it.
That solution requires you to manually enqueue a slider library such as flexslider and add a little custom JS to initialise it.
With the introduction of repeatable field groups you have a simpler alternative that doesn't require the above.
You add a repeatable field group, e.g. slides, to your vessel post type. Each slide should contain only one image field, at a minimum, but could also contain a text field to store a caption, for example.
You then create a slider View to display this RFG (only the RFG, not Vessel posts), and add a Query Filter to limit which RFGs are shown to only those belonging to the current post. See https://toolset.com/documentation/user-guides/creating-sliders-with-types-and-views/ for details about the pagination settings etc. that are required to create a slider View.
Now, typically you would display this slider on a single Vessel post (so the context for the Query Filter is correct).
If you wanted to have a page that listed all vessels (vessel-list) and showed the slider for each vessel, then you would create a View to list all the vessels, and in the Loop Output section of that View you would insert the slider View you created above.