Keep in mind not all dress forms are the same. I’m recovering a vintage ACME dress form, I call her Betty. Betty’s setup is simple and straight-forward. To disassemble her required only reaching inside and unscrewing a series of screws.
After disassembling the back panels (she’s made of a total of 12) I took a couple of photographs to use as reference points later during re-assembly. Then I sprayed the screws I removed with WD-40 so they’ll look and operate like new again when Betty is put back together. She’s getting a complete makeover. I also sprayed Betty’s stand and the metal fittings. She really needed it-she was rusty and corroded. 
In the meantime while the screws soaked and the WD-40 did it’s magic, I removed the old jersey coverings from the panels and discarded them. I also brushed the panels to remove any dirt and dust accumulated over time.
In the end, Betty’s only made of compacted cardboard. 
I made a crude pattern for the first panel I removed, but later decided it would be simplier to go at it alone. 
To re-cover Betty good choices of fabric are muslin, linen or jersey. I decided to use jersey because it has more “stretch”. To recover each panel piece I placed a bead of
Aleene’s Original Tacky Glue along the back edged of the panel, then pulled a pre-cut piece of jersey over the front and onto the tacky glue bead. The ideal is to get a smooth even surface.
The fabric adheres to the glue almost instantly. I continued this process until I’d re-covered all six of the back panel pieces. Then I trimmed away any excess jersey so that Betty’s interior wouldn’t look a mess.
Next, I reconstructed the panel pieces back onto the stand one by one until the entire back side was reassembled.
Okay, now it’s time to do the same with the front panels.
Lastly, I took a hot sponge to the entire form to shrink the jersey to Betty’s contour. I’ll let her dry completely overnight then adjust her the way I like.