Hi @adeel, for starters I would recommend the Stroop tutorial to get to grips with the PsychoPy fundamentals. Also, take a look at the PsychoPy book, for more guidance on building PsychoPy experiments, including a chapter dedicated to running EEG studies with PsychoPy.
Search Pavlovia.org for projects that may be the same or similar to the study you would like to build. From Pavlovia, you can download tasks, and then modify them to your needs. For online studies, I also recommend taking a look at the crib sheet on the forum, if you run into problems with PsychoPy converting your python task to javascript.