I've heard that they don't believe in any god.
It depends on what you mean by God. Buddhism does not have the concept of a almighty, creator (deism), sustainer, creator plus sustainer (theism), destroyer, everlasting god, external controller or owner or creator of the soul, enforcer of karma or retribution and rewards for one's actions, etc. but does mention Deva who are better described as celestial being / deity but which is sometimes translated perhaps loosely or incorrectly into English as gods.
Also see God in Buddhism.
How can I get into buddhism?
Why don't you 1st take a course at a meditation centre. You can locate a centre close to you here: https://www.dhamma.org/en/index, http://www.internationalmeditationcentre.org/global/index.html, http://www.buddhanet.info/wbd/
What kind of books do you recommend to read for starters?
Start with In the Buddha's Words: An Anthology of Discourses from the Pali Canon (Teachings of the Buddha) Edited and introduced by Bhikkhu Bodhi
Can I be a Buddhist without joining any community?
Anybody walking the path (The Noble 8 Fold Path) with a view to come out of stress can be considered a Buddhist. It will be helpful if you are part of a community as it can help you with learning and practice. But also if you join the wrong community it can be detrimental.
You can try https://www.dhamma.org/ or http://www.internationalmeditationcentre.org/. Also http://www.buddhanet.info/wbd/ has other groups which you can try out but be wary that not all forms of Buddist pratice give the same results.
Is there any kind of "secular" Buddhism?
Secular Buddhism as in the west may have gone too far in re integrating Buddhism but inherently Buddhism is secular. Also see answers to this question on Secularized Buddhism
I would like to learn about their vision of life without making any rituals. Is that possible?
Buddhism does have culture which has developed around it and the cultural significance change from country to country. There are not Rites and Rituals in Buddhism itself.