Just offer him food whenever you eat. So normal breakfast time, lunch time, etc. though dinner will probably be earlier than when you eat about 1-2 hours after he last had a milk feed. And I would skip the yogurts (unless they are plain) and juice. If you want to offer flavoured yogurt, buy some plain yogurt and add a little fruit puree to it, but it's not necessary. Avoid those packaged flavoured ones, because like you said, they have lots of sugar. Same with juice. At 6 months, he should still be having mostly formula or breastmilk as liquid to quench thirst, but you can offer him water in a cup too. He probably won't drink much from a cup at his age, but just keep offering it. You'll see his stools change a lot from weaning. My daughter was always constipated from birth, but once she started food, she was going regularly. It was the food that did it, not hydration (she didn't really drink any water until about 9 months). You might try offering more fruits and vegetables and whole grains to see if it helps with constipation. If he's thirsty, offer him water, of course, but keep his milk feeds up so he's well hydrated. No need for juice.
And as for the routine, really just try to offer food when you'd normally eat in your house. That way he gets used to eating when everyone else does as that's what he'll be doing for the rest of his life anyway. And you can offer him as much as he wants, as long as it's healthy, no added sugar or salt, etc. He'll know when he's had enough. When my daughter just started having 3 meals a day (at 7.5 months), our day looked roughly like this:
6am - milk
8am - breakfast
10am - milk
12pm - lunch
3pm - milk
5pm - dinner
7pm - milk
She's 20 months now and the times are all the same, except that she only has a cup of milk before bed.
