Enabling GZIP on my websites

Good day, please may you assist me in enabling GZIP for my domains. I have tried almost everything. I contacted the hosting provider and they sent me the following guide: https://support.plesk.com/hc/en-us/articles/115000716649-How-to-enable-gzip-compression-in-Apache-on-Plesk-server-

I added the lines of code to the .htaccess file and nothing has changed. I do not know where to go from there and this is a vital part of optimising my website. Please let me know if you need to login to my file manager for the website. Please help :slight_frown: