Young West Ham striker Sears has arrived on a season-long loan while ex-Charlton playmaker Ambrose has signed a two-year deal and will provide competition for Carle in midfield.
"They seem like really nice guys and they've settled in with the team really well," said Carle.
"Hopefully they can bring something to the team so we can kick on, and hopefully we'll get a few more in before the transfer window closes and look forward to a successful season.
"Freddie looks decent, he's in good shape and hopefully he can do well for us.
"With Darren it's more known he is a really good player and he's looked good in the first week."