Currently I have my domain name with AWS. I bought it there, because my windows server is hosted with them.
I created a Cloudflare account to put my application in HTTPS, so I changed the name servers which pointed to the AWS servers to point to those of Cloudflare. When Cloudflare has confirmed that the domain name really belongs to me, I can continue.
On the other hand, to continue my approach the only documentation that I found on the forum to help me is this
SSL setup with Cloudflare &hilit=https+cloudflare#p37479
However, I don't have access to screenshots so I can't use this case to help me.
I also looked on the forum how to install an SSL certificate on a Tomcat server looking at this case
https, http2 and pfx certificates, Tomcat configuration>
On the other hand, in the first case, I don't know, it's the KeystorePass

And in the second case I don't know what the certificatechainfile is

Then I tried to install an SSL certificate myself using a Youtube video that showed how to install an SSL certificate on a Tomcat server but unfortunately it didn't work.
Tomorrow when Cloudflare has approved my domain name, I will try without documentation and by myself to make my application functional in HTTPS thanks to CloudFlare but if it does not work.
Would it be possible to help me to do it, because honestly I waste a lot of time on this problem and during this time I can't do other things.
Thank you for your help