How to configure MS SQL server 2008 R2 to allow other computers to access my database both Remotely by internet & on LAN?

I want to access the MSSQL Server 2008 R2 database on my machine from LAN & other remote locations connected to Internet? I am a beginner and does not have a very technical knowledge about the MSSQL Configurations so kindly guide me with the simple step by step guidelines to configure the same according to my needs. I have an Static I.P. if we need one. ...