I have several girls for photos and all the slots for actresses filled, but the working girls only have 1 and I have 4 slots, how do I put more to work?

For recruiting hoes you got to 'tame' them first.

Which means you got to fuck some girls from your fuck buddies list. It could happen some of them are not that kind of girl, then you could only add them to the actress branch. Addiotinally you should be able to fuck them (cocksize and excitement fully loaded) and have enough money to pay for their wish (could also abort recruitment process). If she is into the hoe thing and you waited for the cool down timer, you have to repeat this until she is 100% content with this life (hover over the gauge for exact value, 10 repeats should do the thing). With 100% Bimbofication you could give her an offer, she can not deny.

Alternative way of recruiting (offering a job) is fighting a NPC pimp at the street. Here the best possible girl has max 60 sexappeal. If you know how to fight and could live with this less attractive hoes (the income is lower, but you don't have to deal with keeping them in shape every day) go and get them all from this source;-)