Cindr brands itself as a truly simple website builder and it tries to deliver on that promise buy keeping the featureset to a bare minimum. There are only 8 templates to pick from and the editor is very basic and restrictive (you can't move the blocks wherever you want).
Cindr is built around the "blocks" that you can add to the page (image, text, forms, etc). Unfortunately the blocks aren't very customizable and you start hitting walls pretty soon. Overall it seems like Cindr is underdeveloped and stuck in time, which is a pitty because simplicity is always a strong selling point, as long as it comes with enough funtionality.
There's a forever free plan if you want to play around with it but even at the price of zero there are better alternatives out there.