There is some "how-to's" in the search engine which was very valuable for me.
I have a '73 with a '75 CIS engine. Close inspection revealed a real horror story. There are two gas-fume accumulators (for lack of a better term. They are properly named in the PET schematics along with part numbers). One is under the dash in the frunk. It's an almost square, black plastic item with two ports for tubing. Both tubes were not hooked up. It's also a bear to properly attach so I left it to dangle; very light and not in the way of anything important.
There is another in the driver's side wheel well with two ports. It's pretty big, opaque bottle that looks like a juice container or coffee pot filler. On my car the whole shebang was missing including a clamp to hold the thing in place. The clamp is NLA and may be hard to source. I used a heavy duty bungee cord and a block of 2"x 4" to wedge it in. I found a used "bottle" from
jr@retroautomotiveproducts.com for about $80. Upon closer inspection I determined that all the associated tubing was shot, so I replaced it. There are several places to source evap control tubing and most will tell you what and what it cannot be used for. It's pretty inexpensive and you'll need two sizes all of which is detailed in the PET diagrams.
I decided not to replace the braded lines that exit the charcoal canister and end up in the CIS as they looked OK and the job looked too hard!!
At the bottom of the page I have zero gas smell now and feel I've added a measure of safety to boot.
Best,
Tom