Relationship guide or advice for a 20 year old

Like i have experienced only one relationship in my whole life back in 2023 summer and after that relationship i am single till now and i completely moved on from her in 2-3 months after the break up.

I learned quite a few things while being in that relationship,but things didn't worked out as per my expectations and obviously hers.

Now at this age i am little bit confused about like how do i really start from really starting to the relationship as in my past relationship she was first my friends for quite a time and then me moved to relationship.

So how should i start??