From HTTP to HTTPS

Hello,

I’ve purchased an SSL cetificate, it’s already installed. But now, I need to move my whole site from HTTP to HTTPS. In General Settings, on my website, there is nothing about this and in network’s settings on Network, there is nothing too, only this “Ossdl Off Cdn Url : https://www.mywebsite.com/” and this “Ml User Site : https://www.mywebsite.com/”.
I can access on my website on HTTP and HTTPS, both are working, but I don’t need HTTP anymore, I’d like to move on HTTPS.
I tried, a “https-redirection” plugin but when I activate this, I have about 20 warnings and 5 errors. That says many none secured path are used (cause they still on HTTP), even if the plugin should move the whole site on HTTPS.
And last thing, I’m using Jetpack plugin to put on every posts sharing social buttons. When I Activate the “https-redirection” plugin, or even if i just type a URL of any posts from my website, and I add HTTPS before, it clears all stats about sharing social button from jetpack. But what is weird, that if I come back on HTTP, stats about sharing social buttons, come back too.

Would anyone have an idea how to move the whole site on HTTPS without any errors and how to keep the stats about sharing social buttons?

Thanks.