Hi
I am having trouble dealing with browser popups.
I have to click on a link, which opens up a browser popup window for data entry(form). I need to fill in the form and submit it. If there is any material or video or if someone can share the steps, greatly appreciate it.
Thanks
Welcome to the community
Use application/browser
Click activity
Type into activity
These are what you need to use and indicate the required fields and send data
Cheers
I followed same procedure still got error.
I suggest the free training at academy.uipath.com as it will teach you how to do these basic things.
Its Highlight the element but when I am running the bot, its capturing main window but not pop-up window.
Welcome to the UiPath Community!
It’s because of the concept Full selector and Partial selectors 
(Read this Studio - Full versus partial selectors very well explained)
Answer to your solution:
Your attach browser activity is using full selector and any Ui interactions like click/Get Text/Type Into will use partial selector because we are telling the bot that I’m going to work in the same window.
But are you working on one…No. You got popup that is another window. So that’s why bot is not able to find your popup.
Solution to this?
Use Ui Explorer and check the Full selectors those would be like this.
For Main screen
<html app='chrome.exe' title='ACME System 1 - Work Items' />
For Popup
<html app='chrome.exe' htmlwindowname='WI-Update' title='ACME System 1' />
So If you change the window selecter for your popup activity with correct full selector your bot will understand like where to look for that ui element.
This is one of the most detailed post I have ever written on community 
Thanks,
Ashok 