How to add a whole section using JavaScript?

So I am trying to write a script to add a whole, newly added, section to Adobe Analytics. I am not sure I can do it though, so I will appreciate your help. I thought I should add a class name to the section and use document.getElementsbyClassName but it does not seem to work? I also need to add the nested divs and their styles again using JS?
Here is my code:

<section class="flex-columns" style="
    background-color: crimson;
    height: 450px;
    display: flex;
    justify-content: center;
    align-items: center;
"> 
   <div style="
    top: 132px;
    left: 340px;
    width: 400px;
    height: 400px;
    background: #FFFFFF 0% 0% no-repeat padding-box;
    border-radius: 10px;
    opacity: 1;
    margin-left: 5px;
    margin-right: 15px;
">
    <p style="
    top: 187px;
    left: 391px;
    width: 31px;
    height: 138px;
    text-align: left;
    font: normal normal bold 120px/36px Value;
    letter-spacing: 0px;
    opacity: 1;
    margin-top: 65px;
    margin-left: 30px;
    color: black;
    border-style: solid;
    border-color: black;
">1</p>
    <p style="
    top: 326px;
    left: 391px;
    width: 298px;
    height: 152px;
    text-align: left;
    font: normal normal bold 45px/50px Value;
    letter-spacing: 0px;
    color: #888888;
    opacity: 1;
    margin-left: 30px;
">Find your nearest store</p>
</div>
    <div style="
    top: 132px;
    left: 340px;
    width: 400px;
    height: 400px;
    background: #FFFFFF 0% 0% no-repeat padding-box;
    border-radius: 10px;
    opacity: 1;
    margin-left: 5px;
    margin-right: 15px;
"> 
<p style="
    top: 187px;
    left: 811px;
    width: 66px;
    height: 138px;
    text-align: left;
    font: normal normal bold 120px/36px Value;
    letter-spacing: 0px;
    color: black;
    opacity: 1;
    margin-top: 65px;
    margin-left: 30px;
">2</p>
<p style="
    top: 326px;
    left: 811px;
    width: 298px;
    height: 152px;
    text-align: left;
    font: normal normal bold 45px/50px Value;
    letter-spacing: 0px;
    color: #888888;
    opacity: 1;
    margin-left: 30px;
">Book a free hearing test</p>
</div>
    <div style="
    top: 132px;
    left: 340px;
    width: 400px;
    height: 400px;
    background: #FFFFFF 0% 0% no-repeat padding-box;
    border-radius: 10px;
    opacity: 1;
    margin-left: 5px;
    margin-right: 15px;
">
    <p style="
    top: 187px;
    left: 1231px;
    width: 68px;
    height: 138px;
    text-align: left;
    font: normal normal bold 120px/36px Value;
    letter-spacing: 0px;
    color: black;
    border: 2px;
    border-color: black;
    margin-top: 65px;
    margin-left: 30px;
">3</p>
    <p style="
    top: 326px;
    left: 1231px;
    width: 298px;
    height: 152px;
    text-align: left;
    font: normal normal bold 45px/50px Value;
    letter-spacing: 0px;
    color: #888888;
    opacity: 1;
    margin-left: 30px;
    /* margin-bottom: 0px; */
">Get supported by our experts</p>
</div>
</section>