As Agent requires configuration file to connect to Management Console, installation method varies for each NAS vendor.
Package downloadAgent package should be downloaded from Resilio Connect download page, not from the NAS vendor store.
Resilio Connect product does not have pre-packaged Agent for the next NAS vendors: Netgear, FreeNAS, ASUS, Seagate and others.
You still can attempt to run agent on these NASes as a regular linux binary (you'll need to pick binary architecture conforming your NAS CPU), though it is not guaranteed to work. Please keep in mind NAS installation caveats.