What we do best on usingenglish.com is discuss specific questions about English usage, grammar, etc.
For information on broader topics, you're likely to find more information from other sources, such as Wikipedia. For example, see their article on semantics at Semantics - Wikipedia, the free encyclopedia. Or simply type "semantics" into any search engine, such as Google.
If you're new to the subject of semantics, you could look for basic information in Pashto on Wikipedia.