Complex sentence: But with the steady growth of the Croatian community in following years so the club reformed in 1957 on the 15th of May 1957 the club was registered with the governing federation as an official soccer club.
Split into simpler sentences: But with the steady growth of the Croatian community in following years the club was reformed in 1957. And on the 15th of May 1957 the club was registered with the governing federation as an official soccer club.