This chapter starts on the road. Follow it.
When you get to a roadblock, turn left towards the river.
When you get to the end of the river, turn left. You will see an antenna.
Stick to the road. You will get to a radio tower.
Park the car and get to the building that you can see on the screenshot.
There will be a zombie inside. Kill it. Search the building. Get the goods from the crates in a toilet. Then get to the communication device. Alyx will find out that there is no power.
Get outside and head towards the right side of the building in front of you. You will find a soil bank there. Use it to get on the roof.
Get to the other side of the roof. Collect any goods you can find inside the roofless building. Then get back to the place where you jumped off the roof. There's a hole in the wall. Get inside.
You will find a lift shaft there. Jump in. Then get the medkits if you need it.
You will find that there are some disconnected wires.
To restore the power get towards the shaft. To the left there will be a pallet. Remove it and get the wire.
Connect two outlets with this wire (As shown on the screenshot). Then take the wire that is beneath and get back to where you found the short wire.
Use the longer wire to connect two outlets next to the shaft. Thanks to it, you will be able to get back to Alyx.
Get to the lift and press the button to go up. Not only will Alyx be there but also.. hunters.
Hide behind the wall and fight with hunters. Aim at their heads. What is effective there is shotgun and sub machine gun.
When you kill the hunters inside, get outside and kill the rest of them.