Around now or between now and 12 months is a good time to introduce a couple of solids snacks.
One snack time could be in place of the 11.45am BF, the other would be in place of the 5pm BF. If you like you could offer solids snack and offer the BF too or just solids snack with water.
This means LO gets 2 full BF (WU and BT), 3 solids meals (breakfast, lunch, dinner) and 2 snacks.
At 12 months it your own choice to continue to BF or switch to cows milk, it is also okay for 1 of the 2 milk feeds to reduce so long as the other stays as a good portion. For example at 12 months I switch the BT milk to a slightly earlier supper snack with a sippy of milk, but I kept the WU milk as a big milk drink.
The type of meal, well, healthy balanced meals, he can eat the same as the family so long as the foods are not high in sugar and salt (and contain no honey, fish bones, whole nuts and other choke hazards - the standard rules). I altered my cooking so that DS could eat pretty much everything the adults ate, where I knew he would not like something (eg rice he could not eat) I provided an alternative (chapati or naan or even just a piece of bread or home made pancake).
WRT amount of food per meal, this varies hugely. It really is down to the individual need. Your LO will guide you well and so long as meals are healthy and balanced (across a week rather than every meal including every food group) he will eat to his fill and show clear signs of being finished or wanting more. It is quite normal to have varying appetite too, some days eating lots, other days not so much.