You'll need many buttons.
I used fabric-covered buttons, but of course you may use glass buttons, metal buttons, old or new buttons - your choice. They only have to have a SHANK (that's the little loop on the backside of the button).
If you're allergic to nickel you shouldn't use metal buttons or fabric covered buttons!

Additionally you'll need small pliers (nose- or flatpliers), a bracelet with a closure and as many jump rings (or "split rings") as you have buttons.
The materials should be available in the beading or jewelry-making section of a craft shop.
Do yourself a favour and have an eye on quality materials!

It's your choice how "full" your bracelet will be.
I counted the links between the closure parts and then decided to attach a button to 2 adjacent links, then leave one link blank and then attach a button to the 2 next links and so on.
You can always add buttons later, if you want ;)
Oh: I left the three links next to the closrue blank so I can properly pull it through the closure ring. If you use a different closure this isn't necessary - but you'll see that yourself.
I also relocated the closure ring as the bracelet was too wide for me, and added a nice glass buttons to the free end of the bracelet.

Now open a jump ring, attach a button to it and hook the jump ring to a link of your bracelet.
Carefully close the jump ring with your pliers, you don't want to get tangled on your sweater all day, right?!
Repeat until all buttons are attached to your brachelet and it looks the way you want.

There are 18 buttons (plus the black glass button) on my bracelet.

Do you want to know what's best about it?
Each fabric on each button reminds me of something I've sewn. Either for myself or for a lovely person.

A memory-bracelet is a wonderful thing.
And there's enough space left for more buttons and memories...

♥
K. ^-^