How to change DNS settings?

Thank you. I just realised that the dnscryp-proxy 64bit package is obviously not properly installed. Even though I can start/stop the service now, after issuing the install service command you mentioned above, dns queries are still not diverted to through dns crypt but are still directed to the dns server supplied through dhcp.
While I don’t have the lagging issues any more, since I disabled ipv6, I would still prefer dnscrypt (thus, not so urgent, I can use the wifi now, it’s just not DOH).
How do I install the dnscryp package properly?
I’m a bit afraid of touching resolv.conf after the recovery mode thing was reported:-)