New to the game - i see i have a number of players on the last year of their Contracts. Do i need to have the resigned by end of year or is there time inbetween seasons to get this done?

You must resign them before the end of season stage or they will become free agents.

Also, if you only sign them to a 1yr deal, they automatically will become FA's at the end of the season and you'll have to compete for their services if you want them back