Where to start, by what your code is doing.
Include SolidSyslog.h — nothing else.
SolidSyslog_Log— emit an event.SolidSyslog_LogWithSd— emit an event with structured data attached to that one message. Structured data you want on every message is wired once, on the config.
Include SolidSyslog.h — nothing else.
SolidSyslog_Service— move buffered records to the store and out over the wire. Call it repeatedly, from a dedicated task or an existing loop.
Include SolidSyslogConfig.h, plus one header per component you wire.
SolidSyslogConfig— the struct you fill and pass toSolidSyslog_Create. Each slot takes a component you build first.
Find those components by platform if you know your device (Posix, lwIP, Mbed TLS, FatFs, …), or by role if you know the capability you need and want to see which platform provides it.