Hi @Maciej_K,
Welcome to the project! Your contributions would be welcome here. We indeed try to build a community and help new contributors to get onboard. If you are interested, we have a meetup this coming week.
To start contributing to OpenRefine, have a look at our guide here:
If this guide is not clear enough, feel free to suggest improvements to it (in the issue tracker).
As mentioned in that guide, the first step in this contribution process is to become familiar with what the tool does (see the links in the guide).
Just a small note: perhaps you could avoid using all caps in your writing, as it is basically the online equivalent of shouting, which should rarely be needed here 
Looking forward to your pull requests!