I'm kinda new to this but I heard all the cool stuff to look at happens from day 7 - 11.
P.S. It's true
How old are your chickens? I ask because for one, you won't want to try to set and incubate "pullet" eggs that haven't reached full size and maturity yet.
Also, it can be common for pullets under a year old to either not have the desire to go broody, or worse, start out sitting for a few days and then decide to quit.
Do you know what breeds were used to produce your red sex links? If they weren't breeds that tend to go broody, you may have to wait a while before you have a hen interested in motherhood.
What some folks do is acquire a hen from a breed known for going broody fairly consistently, then setting eggs under her to raise when she shows an interest. That way, you get the chicks from (whatever breed your eggs are) but raised by the nurturing qualities of the broody hen.
I wish you good luck with increasing your flock the old fashioned way! None of my girls have had even the tiniest notion to sit on eggs so far, which is why I decided to give try out the old incubator I found in the shed. It's a bit of a hassle, but you do get a front row seat for all the action when they start hatching!