When should one start translating?
At the moment I follow the recommendations (Basics 1 -> Basics 2 -> and so on). I thought that at some point it is recommended that I should start to translate. Will that happen at some point? Or should I better translate when I think it is OK?
ASAP. Once you finish Basics 1 - go right ahead and translate the corresponding articles in that section. Same for Basics 2. and the rest of them... If you get stuck, then it's time to continue education. Enjoy.
The difficulty of the sentences that are presented to you for translation are adjusted to your current level or a little bit above. So, once you have the basics clear, it should be fine to start translating.