Step by Step.
What you have to do.
Order the new items noting the longest waiting period.
Speak to the contractors to be involved and get prices and
timescales (see managing contractors.)
Make a list of everything to be done in the meantime and draw
yourself up a time line.
For example -
The room has to be emptied before work starts
Joiners and electricians have to be finished before the
plasterer starts and plaster has to dry before the decorator
All straight forward stuff.