On a conventional keyboard it might be somewhat irritating and uncomfortable to constantly move your hand to the arrow keys block or mouse to choose a needed option from IntelliSense popup window.
People familiar with Vim know that it uses keys hjkl to navigate through text. We can easily adopt this approach for VSCode as well. One of the options is to install Vim keybindings extension. The most popular is this one. But Vim way is quite a complex thing and it might take several weeks or even months to master it.
Instead we can just use Alt+j for moving up to the previous suggestion and Alt+k for moving down to the next one.
In VSCode press Ctrl+Shift+P, then type Open Keyboard Shortcuts File, keybindings.json will open. Add in it the next entries:
Now you’re all set.