So I found out I was pregnant few months back

I was initially going to have an abortion as this pregnancy was unplanned and I know most of you will say why didn’t I use protection. I was actually on the implant. It’s making me so down o already have two young babies one of whom as autism. So I decided I couldn’t live with myself to kill a unborn child. My question is I don’t want this baby as heartless as it sounds I just can’t cope with 3. I’ve been searching for couples who can’t have babies. This baby should be with a family who will love her or him. How do I go about adoption? I’ve searched but find it difficult