Basically, I followed the steps here.
Since they are a bit out of date, I recommend the following instructions (by the way I've created a new issue regarding the readme, as soon as my last committed test works, I'll update it).
if you just want to work on the UI testing side, you don't need to download the SDK, neither you don't need to download an openmrs package, said that:
1) Clone the UI test cases repository. If you don't remember the command, you can look at this.
2) You can import the project in Eclipse (I don't have experience with other IDE, but I think they should work as long as they support maven). From Eclipse, you should use File -> Import ..-> From existing Maven project
3) You can try to run one of the test case there with the command "Run as Junit ..."
At the moment, I'm trying to recover ignored tests (the ones annotated with @ignore). In order to avoid to overlap each other, we should agree on which test to work. To this end we can exchange private messages, we don't need to bother others
For developing/fixing tests we have to:
1) open an issue
2) create a branch named with the issued id
Still the instructions here should guide you.
Also, take a look at this while coding
Keep in contact!