Here in this case, to add a link to a website. We are going to use a button to perform the action to take us to a website. And drag the button to the screen and change the properties of the button according to your requirements. It is better to rename the buttons to a name that is easy to remember while we are working with the blocks.
An activity starter is used to link to a website button, so that when the button is clicked it open the website link.
Drag the activitystarter to the screen and rename it accordingly to identify easily in the blocks editor.
In order for App Inventor to realize that the activity starter to perform a certain action in this case to go to a webpage. Check the activity starter is highlighted and we need to type a snippet that tells the App Inventor to what you want to do.
We are going to type android.action.intent.VIEW and make sure the VIEW should be typed in Upper Case only.
By using the blocks editor, we want the components to perform the action. Here in this action, when the button is clicked it should take to a website.
When a website button is clicked what do we want to do? We want the activity starter to do something and in this case to open a webpage.
Follow this tutorial for more information on using Activity Starter Component.
