  The Simons Observatory (SO) will detect and map the temperature and
polarization of the millimeter-wavelength sky from Cerro Toco, Chile across a
range of angular scales, providing rich data sets for cosmological and
astrophysical analysis. The SO focal planes will be tiled with compact
hexagonal packages, called Universal Focal-plane Modules (UFMs), in which the
transition-edge sensor (TES) detectors are coupled to 100 mK
microwave-multiplexing electronics. Three different types of dichroic TES
detector arrays with bands centered at 30/40, 90/150, and 220/280 GHz will be
implemented across the 49 planned UFMs. The 90/150GHz and 220/280 GHz arrays
each contain 1,764 TESes, which are read out with two 910x multiplexer
circuits. The modules contain a series of densely routed silicon chips, which
are packaged together in a controlled electromagnetic environment with robust
heat-sinking to 100 mK. Following an overview of the module design, we report
on early results from the first 220/280GHz UFM, including detector yield, as
well as readout and detector noise levels.
