A global block stays connected to its source. Editing it updates every page where it appears. If you want a change that only affects one page, detach the block first (see How to detach a global block).
How to add a global block to a landing page
1
Open your landing page
Open the landing page you want to add the global block to in the editor.
2
Open the Global Blocks panel
In the left toolbar, click the Global Blocks icon, just below the blue + button. The panel lists every global block you have created, with a search bar to find one quickly.

3
Add the block to the page
Global blocks work just like sections. Drag the block from the panel onto the canvas where you want it, then position it like any other section on the page.
How to edit a global block from the page
Select the block on the canvas. In the right sidebar you will see the Global Block panel, which reminds you that the block’s content is edited in the Global Block Editor and applies to every page using it.