For the vocabulary of the first lessons, should I learn to write these characters as well? Or will it come to me in later chapters?

It won't ever just "come to you", but rather once you start adding characters into your start then you will progress with characters. That being said, it is debatable when is the best time to start learning characters. I wouldn't wait too long personally because I feel the benefits are far too great once you learn more vocab. I have seen far too many characters with similar pronunciations written in similar ways and wholeheartedly recommend some basic character study even towards the beginning of your studies. Start to get the hang of characters at this time and then once you have character basics down pat then your progress will speed up dramatically.

I started learning characters as soon as I started learning the words. Learn the corresponding character for each new word you learn, you will thank yourself for that later on, its faster progress.

Should I learn the Chinese radicals first

It helps immensely. Some characters don't look like they obviously can come from radicals though. Still, learning radicals is immensely helpful.

Thanks

thanks

i am on it for a year now , and i must say , speaking chinese okay , pin yin okay , but writing .. no i dont get the hang of it , i do mis something in my brain to recognise it. much more difficult than korean. but we continue and one day ... well i stop using the translator ;-)

I would say start off just doing the lessons and learn the pinyin for the first couple lessons. Once words start to show up more frequently like: 在 中 的 你 我 想 You should start learning them, especially if they are part of a larger word. Once you start to become familiar with some simple words and can form some simple sentences then it would be a good idea to get heavily into the radicals because that will really help later on with the character learning, but won't bore you early on. It will accelerate the character learning speed and make things easier. There are lists online of the most common simplified characters that are used which is a good place to start, personally I would do that BEFORE doing the Rocket Chinese Writing section Good luck, and let me know if you use this advice and if it is useful to you

I think that the writing part of rocketchinese is very good place to start. It explains the logic of how the characters are built up. The chinese characters are built up of pictures. My theory is that the first persons to use the writing system were groups that was familiar with some pictures. They found out that they could write them on paper and people would know that this paper referred to a famous painting. Later they also realized they could put several pictures together to build sentences. When they wanted to make letters of more complex words, they tried very much to add the lowest amount of symbols to create a new and logical letter.