Hi Kerrie,
Congrats on getting o2. The E tanks are smaller size tanks often used for transport in cars, etc., they hold less o2 than the larger tanks, however the E tanks are a start and should be helpful.
Ideally you will get a large M tank which holds about 200 cubic ft of o2. Before delivery, see if you can get a M tank delivered instead of E tanks, unless you specifically requested E tanks due to transporting in car, to work, etc!?
Each of these tank sizes, E and M, require a connector that attaches the regulator to the valve of the tank.
The regulator determines how many LPM (liters per minute) of your o2 flow. The higher the LPM, the better. 10 lpm is very low for CH's. A high flow regulator that will go from 0 - 60 lpm is ideal. I use 25 lpm to breathe steady and 40 lpm to hyperventilate and after abort I use 15 lpm to sit and breathe after attack is aborted. Many here on this site use demand valves, different subject.
Suggest you do a few things to get you further into the o2 process understanding process...
1st of all, Re-read the o2 tab on the left side of your screen.
Secondly, call Flotec in Indiana and order a connector fitting/high flow regulator that will adapt to your E tanks to offer you high flow LPM such as o - 60 lpm. The E tanks require a CGA 670 fitting and the M tanks or welders tanks require a CGA 540 fitting.
3rd...You will need a non-rebreather mask and are reasonably priced for about $30 bucks from the ch store--left side of your screen.
4th...Helpful to get some energy drinks containing 1000mg of Taurine and Caffeine (such as Redbull, Monster, etc) and SLAM FAST at onset of attack and then try aborting with o2, helps many of us more successfully than o2 alone.
"Knowledge is Power!"....Definitely educate yourself more than your prescribing doctors, o2 people, etc....read how to breathe, position your body when breathing, hyperventilating, intake of 02 vs output of carbon dioxide, how/why o2 impacts dilation of trigeminal nerve, etc.
Again, before the o2 is delivered, see if you can get an M tank delivered, so you don't have to special order a connector for your high flow regulator which you will need for o2 successful aborts. Also to note is if you do not get a high flow regulator from your medical provider or Flotec company, you can pick up a welders regulator from a welding supply store and this regulator will provide high flow o2 to help abort CH's.
Sounds like alot to digest, but you will learn fast, just read and ask questions, we are here for you.

Don't hesitate to PM me for Flotec contact info should you need the phone #