First of all, welcome to the forums.
Second, there is a great collection of tutorials that will teach you just about everything you need to know about Construct 2. For example: https://www.scirra.com/tutorials/73/sup ... reen-sizes
This tutorial will show you how to handle different screen resolutions.
To really become proficient with Construct, you should spend some time going through all the beginner tutorials. Also, if there is a feature you want to learn I would suggest you start there.
I hope that helps you know where to start and good luck with your project.