au naturel
plain sailing
smooth
plaintively
inexplicitly
uncomplicated
purely and simply
paint by numbers
superficially
straightforwardly
uncomplication
decomplication
minimally
mereologically
nothing to it
child's play
explain
supersimple
uncryptic
shallowly
subminimally
simplicially
onefold
haplo-
plainly
cut and dried
unembroidered
sparsely
mediumistically
simplemindedly
lowly
simplish
nonminimally
dizzy
capsule
sparely
noncomprehensively
rudimentary
straightforward
plainspokenly
straight from the shoulder
somewhat
inexpediently
mundanely
easy peasy
slightly
more or less
unembellished
tersely
when it's at home