After Install and default setting, you might want to enable password based proxy change following lines.
Following line will enable .htaccess based password auth.

auth_param basic program /usr/local/libexec/squid/ncsa_auth /usr/local/etc/squid/passwd

Add following line if not exists.

acl all src all

Above line should be above following lines.

acl manager proto cache_object
acl localhost src 127.0.0.1/32
acl to_localhost dst 127.0.0.0/8

Define authentication method for user.

acl thevmc proxy_auth thevmc
</bash>
Allow user to access proxy.
<code bash>
http_access allow thevmc