Follow these steps to install AG.
Add this line to your Spacemacs user config, so Helm can find AG:
(setq helm-ag-base-command "c:\\Users\\Jason\\AppData\\Roaming\\ag --vimgrep")
Make sure to change the path to where you installed AG. See the documentation for an explanation about the vimgrep argument.
Make sure you've setup a project and have a file in that project open.
Open a file in Spacemacs. Type SPACE s a p:
A search window will appear. Start typing, and you'll see fuzzy-matched results:
You can use the up/down arrow keys (or CTRL-j or CTRL-k) and then press the enter key to select a result and navigate to it.
Next: How to setup etags for fuzzy symbol searching in Spacemacs on Windows