How can I use this software to simulate a gnss geodetic network and perform accuracy analysis? Is there a software instruction manual?

No, not really because a simulation is more or less identical to a regular adjustment. The main difference is that observations are obtained from the coordinates of the network points. Thus, true measurements are not required. Just import your points, define some pseudo-observations and start the simulation. Please note that you have to switch the estimation mode: Main menu --> Properties --> Least squares and select Diagnosis adjustment.

Please find below an example taken from the textbook written by Hofmann-Wellenhof:

points3d.txt

SB 4213857.480 1025292.070 4664733.470
KK 4214436.777 1025493.730 4663835.190
KS 4213099.408 1022546.373 4665836.887
LK 4215184.630 1021692.539 4664261.604

gnss3d.txt

SB KK   579.297   201.660  -898.280
KK KS -1337.369 -2947.357  2001.697
KS LK  2085.222  -853.834 -1575.283
SB KS  -758.051 -2745.673  1103.395
LK KK  -747.852  3801.192  -426.417

Just import (main menu --> import) the points as e.g. datum points 3d and the baselines as GNSS baselines 3d. Select Diagnosis adjustment in properties dialog and start the simulation.

Kind regards
Micha