Just out of interest, where are you located? English and Welsh law differs to Scottish law (albeit only minimally) and both differ to American law. Although the general principle of will making is similar in each country, nobody can give you a definitive answer until we know where you are from!
However, I can give you some general advice on English law and will making for your specific scenario.
The important point has already been covered, the witnesses. Providing you have at least two independent witnesses, then the rest is a doddle. Don't worry about writing your will in Olde English, Latin or any other fancy lingo that you might see splashed around elsewhere. As long as you have the correct framework in place, your last will and testament will still be vaild.
The idea of a will is to formalise or at least take a step towards finalising to whom or where your assets are dispersed when you pass away. When writing a will, you need to nominate somebody or a company (usually a firm of solicitors) to act as an Executor. There is no limit as to how many Executors you have, however the general rule of thumb is between 1-3, anymore than 3 and it becomes a bit more of a grind to administer the estate after your death.
Now say for example you are in hospital (on your death bed) and you make a will but you don't want solicitor involvement, that's no problem. You would write your first passage in your will as something along the lines of "I nominate my close friend John Smith, currently of 123 The Street, London, to be my sole executrix of this, my will". What you have done by naming him as your Executor, is give him the legal ability to now undertake full responsibilities of executing your estate. What this means is, it will be John Smith's responsibility to collect all of your assets and distribute them as according to the beneficiaries that you have nominated within your will. He will also be responsible for pay