Can I write my own will?

Yes, you can write your own will.  I'm not an Arkansas lawyer, but some quick internet research suggests that you can do this either by writing it all out by hand (this is called a "holographic will") or by having two witnesses watch you sign it, then sign it as witnesses.  However, simply putting "Last Will and Testament" or words like that on the document, and even listing your children's names, with what you want each one to have under their names, isn't necessarily enough to make it valid.

There are a number of ways to find sample language for wills, but the most reliable, of course, is a lawyer.