I used to run a will-writing company, so I've hopefully got at least a bit of knowledge on this subject.
Any will is legal as long as it has been signed in front of two witnesses and who then append their own signatures. The shortest known will (which was perfectly valid) simply read "Everything to my wife".
My advice is to get hold of a copy of this book
https://tinyurl.com/ywnpac
(It's in most public libraries. It won't matter if you find an older edition because, although some of the rules on intestacy have changed over the years, the stuff about writing a will still remains valid).
Read through the relevant sections of the book carefully and then draft your wills. If you're absolutely 100% certain that you've got everything right, go ahead and sign them in front of witnesses. (NB: The witnesses can't be beneficiaries of your wills. If intended beneficiaries act as witnesses, they lose their entitlements under a will).
However if you've got the slightest doubts at all about your ability to get it right, take your drafts to a solicitor and get him/her to tidy things up for you.
One of the most important things in drafting a will is to allow for "what if?" scenarios, such as "what if my spouse dies before I do?" or "what it Fred, to whom I was going to leave my Rolex watch, dies before me?". Make sure that you consider all of the things that could happen.