сделал how js для пк

assets/js/main.js

@@ -43,3 +43,32 @@ const reviewsSwiper = new Swiper('.reviews-swiper', {
 })
 
 // gymSwiper.destroy();
+
+// how
+
+function howPc() {
+    let itemButtons = document.querySelectorAll('.how-control__item'),
+        itemBlocks = document.querySelectorAll('.how-content__item-block');
+
+    itemButtons.forEach((button, index) => {
+        let block = itemBlocks[index];
+
+        button.onclick = function () {
+            let activeContent = document.querySelector('.how__content').querySelector('.active'),
+                activeButton = document.querySelector('.how__control').querySelector('.active');
+            
+            activeContent.style.height = '0px';
+            activeContent.classList.remove('active');
+            activeButton.classList.remove('active');
+
+            setTimeout(() => {
+                let newHeight = block.querySelector('.how-content__item').offsetHeight + 'px';
+                block.style.height = newHeight;
+                block.classList.add('active');
+                button.classList.add('active');
+            }, 300);
+        }
+    })
+}
+
+howPc();