"Conference calls" = telephone calls with multiple people at the same time

It's a short way to say "phone calls." The way it is used here, it is a noun.

It should be broken down like this: [Post session (work{or}communication) facilitated] [one-hour conference calls] (to be conducted) [two (weeks)] and [four weeks] [following the experience] [to check progress] and [(to) offer coaching] so: "We discussed communicating with the client after the session. We will have a multi-party phone call including the client two weeks after the session. We will have another multi-party phone call including the client four weeks after the session. These conference calls will be for the purpose of checking the client's progress, and to offer coaching to the client if they need it."