Please how can I complete my electronics knowledge
There is no one way, everyone must find their own path. You haven't shared any information about your current knowledge or goals so it isn't possible to give specific information. However, there is some good information on resources here: /learn/learning-center/f/forum/40154/where-are-resources-to-learn-about-basic-electronics
Udergraduate, what subject matter?
Udergraduate, what subject matter?