If you're driving, take the "Rokach" exit on the Ayalon, and follow the signs up a steep hill to the university. Bear right at the first round-about, and go north. You will drive past the building on your left (but the parking lot under it is closed). Park near the second round-about and enter the campus through Gate 14. Walk down the road (100m) until you are under the foot-bridge, where you make a left (south) and join the path coming from the bridge as below.
If you're walking/cycling from the exact sciences buildings, cross the foot-bridge south of the exact sciences library and continue south past the grey wall of the old Wolfson building. Once you see a colonnade start on your left, go up a short flight of stairs, go across the colonnade, and continue diagonally and uphill (going south-east) for some 50m. At the top you will reach the north side of Wolfson Software Engineering building: Either use the side door, or continue around the corner of the building (now going south) to the main entrance.
Here is a map (or in English) of the TAU campus. The Software Engineering is the building that is clipped by the right-edge of the map image - in the English map it is listed as the "Computer and Software Engineering" building.