Generally speaking, avoid using pop-overs, modal dialogs, alerts, and/or lightboxes in your designs. Your question doesn't specify if you're looking for visual design help, but because this is a UX forum I'm going to focus on the broader question.
The key attribute of modals and popovers is that they're disruptive. This is good when you really truly do need to interrupt a user's task and get their attention: for example, their password didn't work and they need to re-enter it to continue.
Some of the key problems with modals include:
- Accessibility issues
- Double-scrolling or scrolling within a modal, esp on mobile web
- Knowing how to exit the modal
- Disrupting the user's task or goal
Philosophically, the point at which a modal ends and a new page begins is a fuzzy line. If you are using a modal to display content, why not just create a new pageview or do inline expansion? The user can then use existing navigation conventions (like the back button, or just continuing to scroll) to get to their previous context.
A deeper discussion is here:
For every interaction the user makes in your app try to rely on motion that encourages a better understanding of the action (like in the physical world).
Take a look at Material design - Choreography.
In the case of Dialogs:
Dialogs inform users about a specific task and may contain critical information, require decisions, or involve multiple tasks.
Autonomous surface creation
Surfaces created without user input, or without a point of origin, should do so using an elegant combination of fading, position, and scaling transformations.