How to speed up my site

Our hosting is provided by AWS, yet our website is quite slow. Offshore Marketers is the name of a website we have. I attach file which show my current site speed. Please Help me to speed up my site.

I checked the loading speed of your main site page and it is 20 seconds! That’s a lot! Google doesn’t like such slow sites. This indicator should be 3-5 seconds. Check your hosting settings, optimize your site. Customers and site visitors will not want to wait that long.