I have unstamped h1b (filed in 2017). Never used. How can i proceed and start working in US

My husband’s employer filed h1b for me in 2017. It got selected in lottery… they got approval notice and receipt number for my application. They have also shared same with me.

They currently dont have any java positions so they have asked me to find job myself.

Now i want to know how can i proceed?

I will be travelling to US on 5 oct on h4 visa. If i am able to find job offer for myself then will that employer need to again file h1 petition for me ( if yes then under cap or cap exempt) OR change of status petiton OR h1 transfer petition OR can start working right away with receipt number without getting h1b stamped … i am not at all sure about the process ahead…

Please guide me how can i start working in US with receipt number and approval notice of my h1b.