Clark, who replaced Stan Ternent at the Galpharm Stadium in December, has already signed Antony Kay from Tranmere and has been linked to Southend defender Peter Clarke.
Clark told the club's official website: "We are quite far down the line on one or two deals and just started to develop others."
He added: "I'm still very busy and I'm talking to a lot of people; managers, agents and players.
"In an ideal world I would have liked to have progressed a few of the deals a bit quicker than I have, but this particular period of time is traditionally quiet as its when everyone takes their break.
"Despite this I'm in contact with different people on a daily basis as I try and bring the right players into the club."