Hi Flavio 6,
Particles (eg.は,が,の,へ,で etc. there are many more) in Japanese, they each have a different function to indicate the relations between words. Some of them have the same function as prepositions in English but others just have other meanings which you just have to learn.
は is a TOPIC MARKER, its function is to indicate the topic in a sentence. Eg. Flavio 6はにほんごをべんきょうしています。(Flavio 6 wa nihongo wo benkyou shiteimasu. / Flavio 6 is studying Japanese). The は after Flavio 6 makes Flavio 6 the topic of the sentence.
The use of はin こんにちは is a bit of a special case so take a look at other sentences for the use of the particle は and I think you will understand.
In おなまえはなんですか, the は(wa) makes the おなまえ(name) the topic of the sentence.
And the answer to the Q could be: わたしのなまえはFlavio 6です(here の is another particle which indicates possession (わたし(I)+の(posession) = my) and は,the topic marker. "My name is Flavio 6". Your name is made the topic of the sentence by the use of は.
Another eg. まで (up to/as far as)
(Kono densya wa Shibuya made ikimasu)
This train(the topic) goes as far as Shibuya.
The German language probably has expressions that serve a similar function. I think eg. eigentlich, ....( )er als ....
As you get familiar with Japanese and how Japanese sentences are structured, you will start to be able to distinguish particles from words. The more words/vocabulary you learn the easier it will be for you to see single words in a sentence.
That's a great start that you already know Hiragana. It will get easier with practice and time. I think it takes time in the beginning as Hiraganas just look like symbols to you but after a while especially after you know more vocabulary they will have more meaning to you and I'm sure they will become more automatic. Good luck!