I would like to know how to incorporate new drawings and have all the previous mark ups imported onto those drawings easily so that i can keep the take offs up to date on the most recent drawings
To address your question, please refer to the Slip Sheet or utilize the Export and Import Markups features.
so it has to be done manually every time, sheet by sheet for a full set of construction drawings?
there is a process for doing this. Batch> Slip Sheet.