@assistance_pls, as @CaptainSqrt2 said, there is a LE integration in Yunohost. You don't need to install manually the SSL cert, in fact I advise you to not do that manually for LE cert. To install one, you must go in your Admin interface, then in Domains. Then you must go in the configuration of your domain by clicking on it. You will see 'Configuration SSL'. You click on it and then, if you domain is correctly set up, you will be able to add a LE cert.
I hope that it will help you,
PS: Pls don't troll ppl, and moreover a Moderator !