Having problems with RewriteRule in .htaccess

My provider was advising me on how to installing Joomla 3.5 from Joomla 1.5. What he didn't tell me was that it would overwrite my existing 1.5 file structure. So I had to rebuild my entire site. We none of the old aliases match the new aliases and some aliases will not longer exists and will create an error. I would like to redirect these errors to either a new page that's closely relevant or a custom 404 error page. Using the .htaccess RewriteRules is what I want to use but a little confused by the syntax.

I want to take www.apolloenergiesinc.com/ct-menu-item-3 and change it www.apolloenergiesinc.com/about-us

I tried the following and none of them worked.

RewriteRule ^ct-menu-item-3?$ about-us [NC]R[301][L]
RewriteRule ^/ct-menu-item-3?$ /about-us [NC]R[301][L]
RewriteRule ^/ct-menu-item-3/?$ /about-us [NC]R[301][L]

What am I doing wrong?