Good shots for your first time in manual mode. Here's some thoughts I had:
#1 - The sky is waaaaay over exposed. Honestly, I don't know how you would fix it because a faster shutter would have under exposed the bridge. You would probably have to use some off camera lighting to get this shot to work. Also, I'm not a huge fan of the composition. I think it's because I want to see more of the bridge itself rather than just the railing. I dunno...
#2 - I like the composition better, but the super shallow depth of field doesn't work for me. Try a larger f/#. You shot at f/4 (I'm guessing that's wide open on your lens?). The smaller the f/# the shallower the depth of field (the area that's in focus.) I would try f/8 or f/11 to widen it a bit so the twig sticking through the railing would be in sharp focus as well. Your sky is blown out again in this shot, but I think it works.
#3 - As far as I see, this shot is technically good (proper exposure, good focus). But I'm not a fan of the subject. It just doesn't make me look very long. I understand this is your first time, but an interesting subject goes a long way.
#4 - Not a very interesting shot, unfortunately. The flash definitely doesn't help. If possible, try to avoid the built in flash. There's only a few rare instances that they help a photo. A speedlight with a swivel/tilting head only costs about $30-40 and the difference is night and day; especially if you get a diffuser for it.
It's a good first attempt at manual mode. I would suggest googling the "exposure triangle" as well as how aperture affects depth of field (DOF). That will help you a lot, I think. You might read up on composing pictures, too. You do pretty well, but there's good information to be had.
TY so much also i understand why you dont like the subject ,, however they are my boys bikes so i geuss that makes the difference to me ,, not that your wrong it is kinda boring to someone else but again my babies