how to patch an LED which isn't in the library?

If you run it in 4 channel mode, you can patch it as a Generic/LED RGBW.  If you want finer grained control, you'll need to make a custom profile (Instructions on how to do this are in the manual).

Edit: It looks like it's very similar to the Studio Due ArchiLED 150 which is in the library in 9 channel mode.  The only difference is the 150 is RGBA instead of RGBW.  You could use this as a base profile and modidfy to make RGBW.

In 16 chanel mode just patch 4 RGBW fixtures consecutively.

In 21 Channel mode patch 3 RGBW and one of the custom fixtures made for step two, or you could build a custom profile that has RED 1, Red 2, Red 3, Red 4 etc etc etc

If you run it in 4 channel mode, you can patch it as a Generic/LED RGBW.  If you want finer grained control, you'll need to make a custom profile (Instructions on how to do this are in the manual).

Edit: It looks like it's very similar to the Studio Due ArchiLED 150 which is in the library in 9 channel mode.  The only difference is the 150 is RGBA instead of RGBW.  You could use this as a base profile and modidfy to make RGBW.

In 16 chanel mode just patch 4 RGBW fixtures consecutively.

In 21 Channel mode patch 3 RGBW and one of the custom fixtures made for step two, or you could build a custom profile that has RED 1, Red 2, Red 3, Red 4 etc etc etc