You don't need to install RIS. Infact, I would recommend you dont. It requires a lengthy setup and native DHCP DNS and AD (as stated above).
What I would consider doing, is copying the i386 directory to a share on your network, build a network boot disk ( this can be tricky if you've never done it before, but it's not impossible) Check
here for some downloadable ones. You will have to modify them of course.
Once you have the bootdisk set-up properly, it is possible to boot the client, have it connect to the i386 share, and then run set-up. In a small scale situation, this is the scenario I recommend. RIS is rarely useful save for large scale operations, due to the requirements and time required. Also, it's NIC driver support is very limited, and adding in your own drivers is difficult enough to annoy a mortal.