please teach me step by step please

OUESTION $3$ TTotal: $23$ marks$]$

Joe has a building project that consists of nine activities. The activities that must be accomplished

in order to complete the project are listed as follows:

a$)$ Construct a network diagram for this problem.

$[7$ marks$]$

b$)$ Determine the expected time, variance, ES$,$ EF$,$ LS$,$ LF and slack for each activity.

c$)$ Determine the critical path to complete the building project.

$[9$ marks$]$

d$)$ What is the expected completion time of the building project?

$[2$ marks$]$

$[2$ marks$]$

e$)$ Calculate the variance of the building project.