How can i point my domain to a SiteGround Hosting

Hello, i have problems in getting my domain to Point to SiteGround platform for hosting. It won’t let me replace the DNS and put my DNS from the hosting platform ( SiteGround).
I’ve tried to even Add Record to my Cloudflare account adding my IP adress to the content but still doesn’t work. What can i do??? How can i make it work?
PS: I have a free plan of website