It takes time for rabbits to become comfortable in their new surroundings and with new people. There is no set time limit about that. It could be days, weeks or months before they are fully comfortable with you.
You didn’t mention if both rabbits have been neutered, or neutered and spayed if the younger one is a female. You will not be able to properly bond them unless they have been spayed and neutered and a little time has passed since their surgeries. Even if you have same sex rabbits and there is no risk of pregnancy, you will need to keep them separated if they haven’t been spayed or neutered and if they are around 3 months of age or more.. Unaltered rabbits can fight and can severely injure on another.
Since you have never lived with rabbits before, you may not be experienced in bonding them (with each other). Here are two good articles.
https://binkybunny.com/BUNNYINFO/tabid/53/CategoryID/9/PID/940/Default.aspx
http://rabbit.org/faq-bonding-multiple-rabbits/
Even though you have worked with rabbits before, it is different when they are living in your home. One of the links I gave you comes from the BUNNY INFO section here. Click on it to see a lot of good information on all the basics of rabbit care.