I want to have a gallery that shows text when you hover

Start by making a grid of divs with background images (use the classes pic1, pic2 etc to create the classes). After that you need to place text with either h or p elements that is showing up where you want them.

<div class="pic1">
  <h3 class="hovergrid">hover texts</h3>
</div>
<div class="pic2">
  <h3 class="hovergrid">hover texts</h3>
</div>
<div class="pic3">
  <h3 class="hovergrid">hover texts</h3>
</div>
<div class="pic4">
  <h3 class="hovergrid">hover texts</h3>
</div>

now we need to add the css to make the text only show up on hover.

.hoverrgid{
    opacity:0;
}

now just tell them to reappear on hover

div:hover .hovergrid{
    opacity:1;
}

now if we want to make it a little bit fancier we can add a transition.

.hovergrid{
    opacity: 0;
    transition: all 1s;
}