I was wondering at what level should someone start translating articles ? I have tried but I found that I am only capable of translating a few words or some sentences but in no way an entire article.
I don't think there's any particular level that guarantees you'll be able to do translations, although at some point Duo does start suggesting them at the end of lessons. At first I think it's easier to start with articles that are already translated and need checking. When you have an English sentence to compare it to already, it's easier to see how the words you don't know fit into a coherent whole. Once you find that checking already translated sentences has gotten easy, then start trying to translate from scratch! (Also, it's perfectly fine to translate one or two sentences and not an entire article. Chances are someone else will finish it, and if not, you can always go back to it later.)
Duolingo used to encourage people to translate from day one. I'm guessing that they would love for people to translate from day one. However, people complained vociferously because they felt they weren't ready. At least that's what it seemed to me, and Duolingo pulled the reminders. Although keep in mind, the current reminder states what percentage one should be able to translate, so people were complaining about feeling inadequate or just the ridiculousness of being told that they could translate like 2%. On the flip side, I think the idea was to go ahead and translate the 2% that you can, not to focus on the 98% that you can't translate.
Regardless, Duolingo removed the reminders, but they did not limit access.
So... go ahead and translate. If you're not ready, stop translating. If you're ready, translate more.
Omagdy, I looked at how far along you are in the tree. My guess is that you just need to practice translation, and you will find that you will pick it up fairly quickly.
Honestly, it's only been recent that I have been able to get through a whole article, and that's just checking translations. I'm proud of myself if I submit a couple sentences that are brand new translations.
I've been translating since I started because translation was recommended from day one when I started. (Sadly, this probably reflects how slow I am at learning Spanish.)