From OMEdit simply drag & drop the components into your model.
Read OpenModelicaUsersGuide.pdf chapter 2 for more information.

Adeel.

Once more, thanks for replaying. I already made a complex model and I know some basics how to connect components and how to make models in OMEdit. Now, I am facing problem that I have a lot of components in one model and the questions was how to hide some of them by putting them (compressing) in one block? The same function exists in Matlab/Simulink where exists some blocks with input and outputs and some logic inside this block. In OMEdit, on examples of motors I saw that for example they put all motors components inside one block; terminal box is also made from a few components etc. I want to do the same with my model; to make some box with image and to programe this block. 
Thanks,
Lala