Securing my internet

Hello Can anyone tell me how I can secure my internet using only a Macbook? Since I had a problem a while ago I have not been able to resecure it. I have gone into my wifi and looked at the assistance, the advanced settings, the airport thingy, checked out online for some guidance to follow but cannot figure this out.
It seems that the online advice refers to aspects that don't apply on my mac.
Any advice? I can't believe it is so difficult. Thanks (nothing too techie please - the blonde version will be good....).