A records are the most basic type of DNS record and are used to point domains to IP addresses. An IP address is the machine-readable address that a human-readable domain name maps to. For instance, google.com has an IP address of 22.214.171.124. You can type that IP address directly into the URL bar of your browser and you'll go to Google's website.
When you want to associate an IP address with your domain name, you do so by adding an A record ("A" stands for "Address") to your domain. Using the example above, google.com has an A record with a value of 126.96.36.199.
CNAME records are another common type of DNS record and are used to point a domain to another subdomain/domain name.
TXT records are used to store any text-based information you want associated with your name that can be obtained when necessary. We commonly see TXT records used to verify domain ownership, but you can use them for associating any arbitrary data with your domain.
NS records are used to point your domain to external nameservers that you manage elsewhere. These identify the authoritative servers that serve a domain's DNS records. Most nameservers will come in sets of two or four and look something like "ns1.nameserver.com" and "ns2.nameserver.com." Please note that using external nameservers is potentially riskier since it is off-chain.
DS records are used with DNSSEC to commit to a child zone's zone signing keys.
TLSA records are used with DANE to commit to the keys a domain uses for TLS.