PF and types of NAT(Network Address Translation)

As you know, at least 3 types of NAT are used. Of course i need to two types of them.DNAT and SNAT. DNAT : hiding server behind NAT, SNAT : hiding your client behind NAT.

Question:

I read a quick tutorial of PF filrewall, but didn’t
distinguish DNAT and SNAT in PF Firewall. How can i define ruleset as DNAT and SNAT?