How can I implement check all, uncheck all, and clear all options for a checkbox list?

const addItems = document.querySelector('.add-items'); //grabs all form items
const itemsList = document.querySelector('.plates'); // grabs plates area
const checkboxes = document.querySelector('.check__all'); // grabs check all button
const uncheckboxes = document.querySelector('.uncheck__all'); // grabs uncheck all button
const clearBoxes = document.querySelector('.clear__all'); // grabs remove/clear all button
const items =  []; // empty area for something to be passed in - we check first if there's an empty area

function addItem(e){
e.preventDefault(); // prevents data to go to client server
const text = (this.querySelector('[name=item]')).value; // grabbing value from name=item form above
const item = { // object with name=item and set to false by default
  text,
  done: false
};

items.push(item); // add item
populateList(items, itemsList); // populated the list
localStorage.setItem('items',JSON.stringify(items)); // put item in local storage so it loads with items
this.reset();
}

function populateList(plates = [], platesList){
platesList.innerHTML = plates.map((plate,i)=>{ // take array of raw data and return data
  return `
    <li>
    <input type = "checkbox" data-index = ${i} id = "item${i}" ${plate.done ? 'checked' : ''} />
    <label for="item${i}">${plate.text}</label>
    </li>
  `;
}).join(''); // turn array in one huge string
}

function toggleDone(e){
if(!e.target.matches('input')) return; // skip this unless input
const el = e.target;
const index = el.dataset.index;
items[index].done = !items[index].done;
localStorage.setItem('items',JSON.stringify(items));
populateList(items, itemsList);
}


addItems.addEventListener('submit', addItem);
itemsList.addEventListener('click', toggleDone);
populateList(items, itemsList);

html {
  box-sizing: border-box;
  background: url('http://wes.io/hx9M/oh-la-la.jpg') center no-repeat;
  background-size: cover;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  font-family: Futura,"Trebuchet MS",Arial,sans-serif;
}

*, *:before, *:after {
  box-sizing: inherit;
}

svg {
  fill:white;
  background: rgba(0,0,0,0.1);
  padding: 20px;
  border-radius: 50%;
  width: 200px;
  margin-bottom: 50px;
}

.wrapper {
  padding: 20px;
  max-width: 350px;
  background: rgba(255,255,255,0.95);
  box-shadow: 0 0 0 10px rgba(0,0,0,0.1);
}

h2 {
  text-align: center;
  margin: 0;
  font-weight: 200;
}

.plates {
  margin: 0;
  padding: 0;
  text-align: left;
  list-style: none;
}

.plates li {
  border-bottom: 1px solid rgba(0,0,0,0.2);
  padding: 10px 0;
  font-weight: 100;
  display: flex;
}

.plates label {
  flex: 1;
  cursor: pointer;
}

.plates input {
  display: none;
}

.plates input + label:before {
  content: '⬜️';
  margin-right: 10px;
}

.plates input:checked + label:before {
  content: '🌮';
}

.add-items {
  margin-top: 20px;
}

.add-items input {
  padding: 10px;
  outline: 0;
  border: 1px solid rgba(0,0,0,0.1);
}

.buttons{
  padding-top: 30px;
}

.buttons input{
  padding: 10px;
  outline: 0;
  border: 1px solid rgba(0,0,0,0.1);
}

.buttons input:hover{
  cursor: pointer;
}

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" x="0px" y="0px" viewBox="0 0 512 512" enable-background="new 0 0 512 512" xml:space="preserve"><g><path d="M495.9,425.3H16.1c-5.2,0-10.1,2.9-12.5,7.6c-2.4,4.7-2.1,10.3,0.9,14.6l39,56.4c2.6,3.8,7,6.1,11.6,6.1h401.7   c4.6,0,9-2.3,11.6-6.1l39-56.4c3-4.3,3.3-9.9,0.9-14.6C506,428.2,501.1,425.3,495.9,425.3z M449.4,481.8H62.6L43,453.6H469   L449.4,481.8z"/><path d="M158.3,122c7.8,0,14.1-6.3,14.1-14.1V43.4c0-7.8-6.3-14.1-14.1-14.1c-7.8,0-14.1,6.3-14.1,14.1v64.5   C144.2,115.7,150.5,122,158.3,122z"/><path d="M245.1,94.7c7.8,0,14.1-6.3,14.1-14.1V16.1c0-7.8-6.3-14.1-14.1-14.1C237.3,2,231,8.3,231,16.1v64.5   C231,88.4,237.3,94.7,245.1,94.7z"/><path d="M331.9,122c7.8,0,14.1-6.3,14.1-14.1V43.4c0-7.8-6.3-14.1-14.1-14.1s-14.1,6.3-14.1,14.1v64.5   C317.8,115.7,324.1,122,331.9,122z"/><path d="M9.6,385.2c5.3,2.8,11.8,1.9,16.2-2.2l50.6-47.7c56.7,46.5,126.6,71.9,198.3,71.9c0,0,0,0,0,0   c87.5,0,169.7-36.6,231.4-103.2c5-5.4,5-13.8,0-19.2c-61.8-66.5-144-103.2-231.4-103.2c-72,0-142.2,25.6-199,72.5l-50-47.1   c-4.4-4.1-10.9-5-16.2-2.2c-5.3,2.8-8.3,8.7-7.4,14.6l11.6,75L2.2,370.6C1.3,376.5,4.2,382.4,9.6,385.2z M380.9,230.8   c34.9,14.3,67.2,35.7,95.3,63.6c-10.1,10-20.8,19.2-31.9,27.5c-22.4-3.3-29.6-8.8-30.7-9.7c-4-5.7-11.8-7.7-18.1-4.4   c-6.9,3.6-9.5,12.2-5.9,19.1c1.9,3.5,7.3,10.3,22.4,16c-10.1,5.7-20.5,10.7-31.1,15.1C352.4,320.2,352.4,268.6,380.9,230.8z    M36.3,255.6l29.4,27.7c5.3,5,13.6,5.1,19.1,0.3c53.2-47.6,120.7-73.7,190-73.7c26.9,0,53.2,3.9,78.5,11.3   c-29.3,44.6-29.3,102,0,146.6c-25.3,7.4-51.6,11.3-78.5,11.3c-69,0-136.3-26-189.4-73.2c-2.7-2.4-13.4-6.3-19.1,0.3l-30.1,28.3   l5.7-40C42.2,293,36.3,255.6,36.3,255.6z"/><circle cx="398.8" cy="273.8" r="14.1"/></g></svg>
        
<div class="wrapper">
  <h2>LOCAL TAPAS</h2>
  <p></p>
  <ul class="plates">
    <li>Loading Tapas...</li>
  </ul>
  <form class="add-items">
    <input type="text" name="item" placeholder="Item Name" required>
    <input type="submit" value="+ Add Item">
  </form>
  <div class = "buttons">
  <input type="submit" class = "check__all" value="Check All">
  <input type="submit" class = "uncheck__all" value="Uncheck All">
  <input type="submit" class = "clear__all" value="Clear All">
  </div>
</div>