Install acme.sh with the following command or following the instructions on their wiki:
curl https://get.acme.sh | sh -s email=your@email.com
Following the instructions on acme.sh wiki (How to use DNS API - Cloudflare) I created a token in under My Profile > API Tokens in Cloudflare with permissions for Zone.DNS to all zones.
Then I added the token my ~/.bashrc file:
export CF_Token="token123"
I requested the cert:
acme.sh --issue --server letsencrypt --dns dns_cf -d adguardhome.csilo.ca
...
truncated the output :)
...
[Wed Jun 26 15:14:03 EDT 2024] Your cert is in: /home/connor/.acme.sh/adguardhome.csilo.ca_ecc/adguardhome.csilo.ca.cer
[Wed Jun 26 15:14:03 EDT 2024] Your cert key is in: /home/connor/.acme.sh/adguardhome.csilo.ca_ecc/adguardhome.csilo.ca.key
[Wed Jun 26 15:14:03 EDT 2024] The intermediate CA cert is in: /home/connor/.acme.sh/adguardhome.csilo.ca_ecc/ca.cer
[Wed Jun 26 15:14:03 EDT 2024] And the full chain certs is there: /home/connor/.acme.sh/adguardhome.csilo.ca_ecc/fullchain.cer
Finally I added the cert & key paths provided by acme.sh into the Adguard Home GUI’s certificate settings.