Custom Java Library in Ecclipse Robot Framework

Hello Everyone ,

I am new to this Robot framework , we are using it as plugin in Eclipse and its keyword driven approach is really good for manual testers.
Before this we were using Selenium Java TestNG framework where we have written customized methods over selenium Java libraries.
Now as we are switching to Robot Framework , Is there any way where I can import my existing class/library so that my written methods can come as keywords drop down and I can use the same.
I tried many videos/tutorial but dint get concrete steps /response.

Can some one please assist .

Thanks Much!