Boys Casual Business Stretch Slim Fit Elastic Waist Pants Cas 1.108.349 9sims4.zip

Unzip the archive, then copy the .package and .ts4script files into Documents/Electronic Arts/The Sims 4/Mods. Script mods also need Game Options → Other → Enable Custom Content and Mods and Script Mods Allowed, then a restart. Sims and households go in the Tray folder instead.