DO NOT CREATE YOUR OWN WORLD OR ATTEMPT TO GO TO ANY OTHER SERVER EXCEPT MINE
On the desktop find the launcher and double click on it.
Make sure the drop down menu says MinecraftEdu then click on Launch:
Then click Direct Connect:
1st time players or very new to Minecraft type in Server Ad 126.96.36.199:
Type in this Server Address: 10.20.2.19
Then type in your First name Last Initial as player name
Here are some helpful guides.
This is a very good tutorial on surviving your first night:
Probably the most helpful and detailed resource available is here:
Additionally, you can find many helpful video tutorials on Youtube.