Get autocomplete to display candidates only when tab is pressed

Question

I've set up auto-complete on emacs to display completion candidates, and it seems to be working well so far. I'm finding the constant display (and changes in display) distracting when I type, and I would like to get auto-complete to show completion candidates only when I press a key, preferably the tab key.

Can this be done? Here's my current configuration (including yasnippet, which I want to respond to the tab keypress first):

(use-package yasnippet
  :ensure t
  :config
    (yas-global-mode 1)
  :pin gnu
)

(use-package auto-complete
  :ensure t
  :config
  (progn
    (require 'auto-complete-config)
    (add-to-list 'ac-dictionary-directories "~/.emacs.d/ac-dict")
    (ac-config-default)
    (ac-set-trigger-key "TAB")
    (ac-set-trigger-key "<tab>"))
  :pin melpa
)

This shows completion candidates continuously.

Answer 1

(setq ac-auto-start nil)

ac-auto-start

Specify how completion will be started. t means always starting completion automatically. nil means never started automatically. An integer means completion will not be started until the value is more than a length of the completion target string.

It's described in the Auto-Complete User Manual.