does the netgear router have NAT capabilities? if so hook the dsl modem to the internet and the netgear router to it. The router will get it’s outside address from the dsl modem and will provide internal private addresses to 15 workstations. How many ports does the linksys switch have? If it is a 24 port you would then plug the router to one port and the 15 workstations to the others.
If you want to do bandwidth provisioning so that some workstations get some bandwidth and others are limited to a set max bandwidth I do not believe you can do that with the equipment you have described. If you have an old pc and two nics you can setup an IPCop firewall that you can do that with. The OS is free and works great. Then you will also be able to log all traffic coming in and out of your network, setup groups of who can have internet access and who cannot. You can also use the IPCop firewall as your dhcp server and do away with the netgear router altogether. It will also handle vpn access if you need to vpn in from work.