Not a particularly complex model but...

Thorough inspection of glue joints and covering
Reading the manual
Rereading the manual
Cutting out and fitting canopy - gonna tint it?
Assembling wheel pants (and installing) This can take awhile for some planes
Fitting the cowl - including cutouts for engine
Install fuel dots etc
Hinging
Decals ...
Beefing up landing gear and firewall...

A lot of this stuff may not apply to an introductory trainer but is part of many ARFs. I would probably figure on 15-20 hours assuming that there are no major mods and I don't have to run out to pick up something I forgot. (Where is the spinner and aileron extensions?)

Ross