You can make this as simple or complicated as you wish. Essentially, your choices will be starter, grower,(there is also finisher, though that is geared more towards meat birds) and layer. In theory they follow along on each other in a progressive manner between hatch and 18+ weeks. Starter is finer particles of feed - grower is coarser pieces. The actual nutritional differences between starter and grower are, imo, minimal with regards. Layer feed has significantly higher calcium content (4% vs <1%) - this is to provide the calcium laying birds need to shell and expel their eggs.
Most "schedules" will call for starter for the first 6-8 weeks and grower from the end of starter to the point of lay (18-20 weeks on most feed bags) at which point you would switch to layer ration.
The alternative approach (which I employ) is to feed a grower ration at all times - I start my new babies on it and feed it to my entire flock for their lifetime. I use Flock Raiser, but any grower ration can be used. This is especially nice with mixed flocks (male/female or actively laying and not actively laying due to age, molt, etc) as it eliminates trying to worry about who is eating what, having to house birds separately, etc. To make up for the calcium that is not in grower ration, simply provide free choice oyster shell on the side for those birds who need it (those currently producing eggs) to take as desired.