For those who are interested, you can just follow the easy steps to install it below.

<script type="text/javascript">
/*<![CDATA[*/
// Smooth scroll
!function(){function e(){var e=!1;e&&c("keydown",r),v.keyboardSupport&&!e&&u("keydown",r)}function t(){if(document.body){var t=document.body,o=document.documentElement,n=window.innerHeight,r=t.scrollHeight;if(S=document.compatMode.indexOf("CSS")>=0?o:t,w=t,e(),x=!0,top!=self)y=!0;else if(r>n&&(t.offsetHeight<=n||o.offsetHeight<=n)){var a=!1,i=function(){a||o.scrollHeight==document.height||(a=!0,setTimeout(function(){o.style.height=document.height+"px",a=!1},500))};if(o.style.height="auto",setTimeout(i,10),S.offsetHeight<=n){var l=document.createElement("div");l.style.clear="both",t.appendChild(l)}}v.fixedBackground||b||(t.style.backgroundAttachment="scroll",o.style.backgroundAttachment="scroll")}}function o(e,t,o,n){if(n||(n=1e3),d(t,o),1!=v.accelerationMax){var r=+new Date,a=r-C;if(a<v.accelerationDelta){var i=(1+30/a)/2;i>1&&(i=Math.min(i,v.accelerationMax),t*=i,o*=i)}C=+new Date}if(M.push({x:t,y:o,lastX:0>t?.99:-.99,lastY:0>o?.99:-.99,start:+new Date}),!T){var l=e===document.body,u=function(){for(var r=+new Date,a=0,i=0,c=0;c<M.length;c++){var s=M[c],d=r-s.start,f=d>=v.animationTime,h=f?1:d/v.animationTime;v.pulseAlgorithm&&(h=p(h));var m=s.x*h-s.lastX>>0,w=s.y*h-s.lastY>>0;a+=m,i+=w,s.lastX+=m,s.lastY+=w,f&&(M.splice(c,1),c--)}l?window.scrollBy(a,i):(a&&(e.scrollLeft+=a),i&&(e.scrollTop+=i)),t||o||(M=[]),M.length?E(u,e,n/v.frameRate+1):T=!1};E(u,e,0),T=!0}}function n(e){x||t();var n=e.target,r=l(n);if(!r||e.defaultPrevented||s(w,"embed")||s(n,"embed")&&/\.pdf/i.test(n.src))return!0;var a=e.wheelDeltaX||0,i=e.wheelDeltaY||0;return a||i||(i=e.wheelDelta||0),!v.touchpadSupport&&f(i)?!0:(Math.abs(a)>1.2&&(a*=v.stepSize/120),Math.abs(i)>1.2&&(i*=v.stepSize/120),o(r,-a,-i),void e.preventDefault())}function r(e){var t=e.target,n=e.ctrlKey||e.altKey||e.metaKey||e.shiftKey&&e.keyCode!==H.spacebar;if(/input|textarea|select|embed/i.test(t.nodeName)||t.isContentEditable||e.defaultPrevented||n)return!0;if(s(t,"button")&&e.keyCode===H.spacebar)return!0;var r,a=0,i=0,u=l(w),c=u.clientHeight;switch(u==document.body&&(c=window.innerHeight),e.keyCode){case H.up:i=-v.arrowScroll;break;case H.down:i=v.arrowScroll;break;case H.spacebar:r=e.shiftKey?1:-1,i=-r*c*.9;break;case H.pageup:i=.9*-c;break;case H.pagedown:i=.9*c;break;case H.home:i=-u.scrollTop;break;case H.end:var d=u.scrollHeight-u.scrollTop-c;i=d>0?d+10:0;break;case H.left:a=-v.arrowScroll;break;case H.right:a=v.arrowScroll;break;default:return!0}o(u,a,i),e.preventDefault()}function a(e){w=e.target}function i(e,t){for(var o=e.length;o--;)z[N(e[o])]=t;return t}function l(e){var t=[],o=S.scrollHeight;do{var n=z[N(e)];if(n)return i(t,n);if(t.push(e),o===e.scrollHeight){if(!y||S.clientHeight+10<o)return i(t,document.body)}else if(e.clientHeight+10<e.scrollHeight&&(overflow=getComputedStyle(e,"").getPropertyValue("overflow-y"),"scroll"===overflow||"auto"===overflow))return i(t,e)}while(e=e.parentNode)}function u(e,t,o){window.addEventListener(e,t,o||!1)}function c(e,t,o){window.removeEventListener(e,t,o||!1)}function s(e,t){return(e.nodeName||"").toLowerCase()===t.toLowerCase()}function d(e,t){e=e>0?1:-1,t=t>0?1:-1,(k.x!==e||k.y!==t)&&(k.x=e,k.y=t,M=[],C=0)}function f(e){if(e){e=Math.abs(e),D.push(e),D.shift(),clearTimeout(A);var t=D[0]==D[1]&&D[1]==D[2],o=h(D[0],120)&&h(D[1],120)&&h(D[2],120);return!(t||o)}}function h(e,t){return Math.floor(e/t)==e/t}function m(e){var t,o,n;return e*=v.pulseScale,1>e?t=e-(1-Math.exp(-e)):(o=Math.exp(-1),e-=1,n=1-Math.exp(-e),t=o+n*(1-o)),t*v.pulseNormalize}function p(e){return e>=1?1:0>=e?0:(1==v.pulseNormalize&&(v.pulseNormalize/=m(1)),m(e))}var w,g={frameRate:150,animationTime:800,stepSize:120,pulseAlgorithm:!0,pulseScale:8,pulseNormalize:1,accelerationDelta:20,accelerationMax:1,keyboardSupport:!0,arrowScroll:50,touchpadSupport:!0,fixedBackground:!0,excluded:""},v=g,b=!1,y=!1,k={x:0,y:0},x=!1,S=document.documentElement,D=[120,120,120],H={left:37,up:38,right:39,down:40,spacebar:32,pageup:33,pagedown:34,end:35,home:36},v=g,M=[],T=!1,C=+new Date,z={};setInterval(function(){z={}},1e4);var A,N=function(){var e=0;return function(t){return t.uniqueID||(t.uniqueID=e++)}}(),E=function(){return window.requestAnimationFrame||window.webkitRequestAnimationFrame||function(e,t,o){window.setTimeout(e,o||1e3/60)}}(),K=/chrome/i.test(window.navigator.userAgent),L="onmousewheel"in document;L&&K&&(u("mousedown",a),u("mousewheel",n),u("load",t))}();
/*]]>*/
</script>

Then click Save theme and finish. For the results you can check and see the difference with before using the Smooth Scroll Effect on your website.

That's a tutorial about How to Add Smooth Scroll Effects to Blogger. Hopefully with these fairly short tips, it can be useful and useful for all of you. Thank you and good luck.