You are set up
There is nothing to configure and no account to make. Open any page, click the Search Picker icon in your toolbar, and give it a short name. After that, type s, press Space, then that name in the address bar to come straight back.
How to use it
From the address bar
Type s, press Space or Tab, then start typing a shortcut name and press Enter.
The space or tab is what hands the address bar over to Search Picker.
Typing s/name straight in will not work: the browser has
no way to know the slash was meant for an extension, so it treats the
whole thing as a search. That is why shortcuts are written
sname here
rather than s/name: the box is the space bar.
To use one of your own search engines, type its keyword and then your
query, for example g some words.
From any page
Press Ctrl+Shift+Y to open the picker over the page you are on, or click the Search Picker icon in the toolbar to save the current page as a shortcut.
If a keyboard shortcut does nothing, another extension has probably
claimed it. Open chrome://extensions/shortcuts to see
whether it is assigned, and set your own if not.
Your shortcuts
Your search engines
A search engine is a shortcut that takes something with it. Put
%q in the URL where the search term belongs, and then
typing its keyword followed by your words searches that site straight
from the address bar.
Sync across devices Optional
Everything above is saved on this computer and works without an account. A free account gets you the same shortcuts in every browser you sign in to, tags in the picker, and a page on the website for editing them in bulk.
Create a free account, then copy the key from your dashboard under "Browser extension" and paste it here.
Connected.
Disconnecting keeps every shortcut on this computer. It only stops them being kept in step with your account.
Deletes every shortcut and search engine stored in this browser. Anything in your Search Picker account on the website stays where it is.