First they're both youngsters, so playing a lot when together is normal and natural.

Do you use a clicker? If not I would strongly suggest you get one, load it with each dog SEPARATELY and start with basics.
With one being only six months old, it's not going to be easy to train them together, but start with a good 'sit' then work on a good, strong 'stay'. Using a clicker will make this a LOT easier, as dogs respond to the clicker/treat very quickly and easily. I wouldn't work on anything else until I had one sitting and staying while you work with the other dog on maybe basics like down/drop. It's going to take some time and patience though with two youngsters.
Also work on getting them to focus on you. Again with the clicker/treat, just ask for 'watch me' and click treat when they look at you and give you eye contact. This will help them to learn to focus on you and LOL not on each other!
With walking them, again work in your own garden first, that way you're in a secure environment. Work for short periods only with them together.
Also, I would work with them on heel work, separately, then move on to working with them together once they BOTH have a good strong sit/stay while you're working with the other dog.
Take it easy, just short sessions and release them for a good play time in between each session.