So, you used the client “gethttpsforfree.com”.
As that’s a manual client, you’ll have no way to automate the renewal, as the issuing wasn’t automated as wel. You’ll have to do the whole process again as the YouTube video explained, with a few remarks:
The account key you can re-use. I assume you have everything from the first certificate issuing stored somewhere safe, so you can just grab the old account key.
You can either generate a new CSR in cPanel (and use a new private key) or re-use the old CSR and private key. That’s up to you.
Aside from the two remarks above, you’ll have to follow every step again as explained in the video.