Assuming you have a standard setup, you need to connect your iPad to your PC and use iTunes to update it. Click on the iPad device in the left hand panel of iTunes and you will see 2 buttons. Update and Restore. Press update and the rest of the process should be automatic.
Since your iPad is on a very old version of IOS now, the update may run into problems. If this happens, you may need to restore to a factory fresh state, since an upgrade from such an old version may not go as planned! But we will cross that bridge if we come to it
The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.