Continuing.. Now you can switch on your computer again and hopefully the primary slave (your new drive) will be detected. If not, (assuming it is installed correctly) then you'll probably have to change the bios settings to detect the new drive. I could give you a general overview but since bios are different for different machines, it may not be accurate.
If you would like an overview then please post a followup.
There is a possibility that, if you have a cd or dvd drive, then it is the primary slave. In this case the new drive would have to be installed as the secondary master or slave. This is the other IDE cable in the computer (not the floppy drive cable which is narrower). If there is not one present then you will have to buy one. However, they are relatively cheap. Obviously if installing it a secondary master the jumper will need to set to master.
If you have any further questions, please post a followup.
I apologise for the length of this response but it would not be possible to make it thorough had it been shorter. Given the apparent little experience in this area that you had I felt the more thorough, the better.