Complex sentence: He was involved in Plast in exile, as well, and took part in a camp celebrating the 45th aniniversary of Plast in "Plastova Sich" in Canada in 1957.
Split into simpler sentences: He was involved in Plast in exile, too. So he took part in a camp celebrating the 45th aniniversary of Plast in Plastova Sich in Canada in 1957.