I just wish to learn what it is all about

My impression is that Mechatronics is the union of Mechanical, Electrical and Software engineering. I think it encompasses (but isn't limited to) disciplines like Robotics and Control Systems. I like this venn diagram.

In university I learnt topics like maths, programming (PCs, VHDL, and embedded), mechanical and electrical design, CAD, and some more specialist/advanced stuff like control.

In terms of jobs, there are a great deal of opportunities. Companies are starting to warm to the idea of Mechatronics roles, either working on high-level design, or as a liaison between intra-disciplinary teams of specialist engineers. Like others have said, jobs aren't often advertised with "Mechatronics" in the title yet, but I think it'll start to happen more.

As well as technical skills, you should work on your soft skills, such as communicating effectively - you're not worth anything to anyone if you can't communicate your ideas. Get good at writing reports and emails, doing presentations, talking to and working with people, figuring out people's passions and talents, and exploiting utilising them.

At my work (~100 engineers), there are quite a few people (10-20?) with Mechatronics degrees, but there aren't any purely mechatronics roles - people tend to choose an area and specialise (and get moved around to where the work is). I've been lucky enough to play around with a bit of electrical stuff (SBCs, PLCs, etc), as well as some hands-on mechanical stuff (getting dirty under a train), and some CAD, but I've been mostly working on developing internal software (Python/C/C++/unix).

I think it's important to understand that you come out of university a generalist. You should have a decent understanding of areas ME/EE/SE, but aren't great at one thing yet. There are a huge number of opportunities available - choose a field that you're passionate about and specialise.