Three of these have been suggested to need a how to guide. (Including one I did not have in the list for just this reason.)
First of all is Ublock Origin. It is a classic adblocker that can do much more than most other such extensions. Here is how to configure it.
Click the Ublock Origin icon in the browser.
(Obviously it is the icon surrounded in green.)
That brings this little menu down. Click the title of the menu where it says Ublock Origin.
(Again, the green highlight shows where to click in case I am being too unclear.)
That brings us to the Ublock Origin Dashboard. Click the "3rd-Party Filters" tab and set it similar to this. You have a lot of options here, but this seems to work everywhere I go on the Internet. Your mileage may vary.
Once you change, add, or remove any filters, you will see "apply" in the upper right corner. Click that to save your changes. It will automatically update the filters for you.
Now Request Policy and NoScript work almost identically. So I am just providing instructions for Request Policy. Too many sites fail to work as desired with NoScript, so I do not use it most of the time.
Lets say you open Random.org and want to see how it works.
Like the last few images, the green highlight is around the icon to click for this extension to do what it does best. That brings you to this.
It shows you each domain attempting to load content into the page. See the options at the very bottom? Those are the only ones you should ever use unless you are really certain you know what you are doing.
If you load a site and the images do not load with the text, or the formatting is all messed up, it is likely because it is being blocked by this. Use the Temporarily Allow option on the very bottom to see if that fixes it. If not, you may have more domains to permit. But be warned not to use the "Allow Requests from" option on any site you are not certain you trust. Temporarily allowing a bad site will usually not be a terrible choice, but if you set it to allow them without using the temporary option, you will have to hope the site does not mess things up that you cannot fix, and it will remember all but the temporary permissions assigned here next time you load the browser too.
Questions? Ask away.