Complex sentence: Stallknecht's carpentry training served as preparation for his work on interiors and furnishings design, such as his 1968 design for the "Selio" convertible armchair-ottoman-daybed, although as of 2013 it had not found a manufacturer.
Split into simpler sentences: Stallknecht's carpentry training served as preparation for his work on interiors and furnishings design. In 1968 he invented the "Selio" convertible armchair-ottoman-daybed although as of 2013 it had not found a manufacturer.