Hey,
I started running facebook campaign and I was very happy with CTR (4.27%) and 115 clicks but than checked my google analytics and its empty.
I am boosting my page post.

Stats looks like:

What confuses me that when I hover over "Clicks" fb says:
"A click on an ad that sends the viewer to your website or app (ex: someone clicks your ad and is taken to your website). Other types of engagement with an ad (ex: likes, comments, shares) are not counted as clicks."
But when I select "Website Clicks" I get 0. Which ones I should use to know how many real clicks I get to website or none of them works if it is post boost with link in comment?
Clicks = interactions with your ad.
Website clicks = clicks of an external link.
In that description they misnomer slightly - the last part should read ...are not counted as website clicks.
You are charged for all actions, not just the website clicks, so people liking your ads costs you $ if bidding CPC.
As for putting a link in your post text, yes that's a slightly different story. I'm not actually sure how FB tracks those and the charging mechanics, it's been a while since I have done any ads with links in the post text. Can someone confirm? In any case, if your 3rd party tracking is registering no clicks... chances are it's because you're not getting any, hence Facebook's stats which show some ~100 likes/shares/comments, so at least 90% of your engagements are not external link clicks... that much is clear.