The small growing points with leaves that stick out from the main stem of the tomato. In the angle between th main stem and the proper left bract. Just nip them out with your fingers. You are doing this to allow the plant to focus on producing fruit.

They are shoots that grow in between a leaf stalk and the main stem, up the side of the plant. They will turn into branches if you leave them. Snap them off when they are small.

Our comments crossed Moongrower :)

I'm sorry but I don't understand

Look at the place where a leaf joins the main stem. You'll see a little branch coming out from the join. Snap it off.
I can't explain it better than that.

Having pulled the photo to my desktop so that I could look at it right side up there don't appear to be any side shoots right now or, if there are, I'm not seeing them. Just lee pan eye on the plants and if you see any growth in the angle between the main stem and a branch simply remove.

Having had a good look at your plants, the bottom photo shows perhaps the best example, although there are others. look at the top of the plantpot and about 1 foot up on there's a branch that's POINTING DOWNWARDS.
Look where that branch meets the stem, and hust above that point there appear to be at least oneof these small suckers AT ABOUT 45 degrees. ( as I was told they were called.)
Then look closely all the way up the stem and you will find others.
I'm still a beginner myself but I remove these suckers most days.

I understand now. Thank you both for taking the time to look at the photos and for explaining all that. Now I know what to look for. Thanks again.

You're very welcome N, I've been a member for several years ( beginner) but this is just the second time I've been able to help, so it quite made my day.