如何将自定义网址wordpress转换为友好网址

I have one problem, Once page in WordPress need a parameter in $_GET. I got URL,

example: homepage.com/something/?param1=someString,

I would like to get homepage.com/something/someString <--- someString would like to get in table $_GET. I tried by htaccess but it's not working.

RewriteCond %{REQUEST_URI} ^something/ [NC]
RewriteRule ^/something/([a-z]+)/?$ /something/?param1=$1 [L]

Additional when I tried homepage.com/something/someInteger It's going to the correct page, "something" but when I tried homepage.com/something/someString <---

It's going to 404 page, why?

Somebody any ideas?