Hello,
Please try to add this code in custom css http://prntscr.com/hbofkm:
.products-grid .product .product-image-wrapper, .sidebar-position-without .products-grid.product-count-3 .product {
text-align: center;
}
.products-grid .product .product-image-wrapper {
margin-top: 15px;
}
How to create custom.css you can watch in this tutorial https://www.youtube.com/watch?v=Qok2zRedRMY.
Regards