You will need a good level of English and be sure, that they REALLY want you to be a good team player and be nice around your coworkers. Of course, some positions requiere high level of technical skills, but in my experience their primary focus is how you are as a person.
I was recommended by two employees and they contacted me the by email in less than a week.
They review my LinkedIn account and then we made a Skype interview in with we talk mostly about me and my background with out been very specific about anything.
Then they sent me a exercise to develop a gadget using Angular 1.5, html5, css3 and some classical pure JavaScript problems. They don't have a time limit for you to send the solutions but I recommend you to take no longer than two or if possible one week to make it.
Then they sent me a feedback, they put a lot of focus on code clarity and good practices, I recommend you to avoid shorthands and "clever code" in favour of more readable and maintainable code with some comments.
If you want, they give you the opportunity to review your work with their recommendation and send it again (if this is the case, do it! and do it ASAP)
At this point I received a call from another company and I decided to go with them instead of Olapic for personal reasons. Anyway this is a great and fun company to work with, they have some of the best benefits that I have seen in companies around here and I don't discard to give it another try if I have the chance.
I'm not sure... but I think that you have another two interviews (if you pass the technical one). Both personal ones and I think that one of them is a lunch with your future team.