I would like to have my articles…
I would like it to have the links to all the posts…
Keep what you already have for the posts and make a Custom Menu for your articles. Dashboard > Appearance > Menus is where you can do that, then place a Custom Menu widget wherever you want it and select your new Custom Menu. Also, you can tell that Custom Menu to automatically add new pages (articles), if you wish.
note: I believe you could even do the same with Custom Menus for categories of posts.
Agree with @leejosopho but you may also want to try this plugin:
https://wordpress.org/plugins/recent-posts-widget-extended/
It has a lot of cool features like sort order, limit posts to specific categories (which is as I understand what you need), thumbnail and excerpt display and more. I use it on many sites and it works like a charm.
Great! Thank you to both of you for your help. This helped a lot.