Where is my .htaccess file?

Ok now I get this error...

If your .htaccess file were writable, we could do this automatically, but it isn’t so these are the mod_rewrite rules you should have in your .htaccess file. Click in the field and press CTRL + a to select all.

I looked and I could not find .htaccess file so I created one and put it in wp-admin.
chmod it to 775
But still it gives me a error?

I got the post to give the correct url
......google/search-engine-optimization-for-longer-keywords/
but when I click on the heading to go to the post I get a 404.... is the htaccess error
the reason?

Andy