Hey man, I can help you out with some AM2 stuff!
First, you don't have to put the Obelisk
on the gateway, it just has to be close enough to link it to the gateway (within 10 blocks). Once you have that, you need to link it to the keystone receptacle via the Crystal Wrench - just right-click the obelisk once, then right-click the keystone receptacle. You should get a "Paring Successful!" message in the chatbox. Now you just have to load up the Obelisk (bring a hardened tank full of liquid etherium, you'll go through a lot for teleportation). I have an alternative source of energy that I feel is more useful for the Gateways that I'll go over in a minute.
Next, you need to make sure that you have at least 2 Gateways set up, not more than 12,000 blocks apart (limits of the mod). Then, you have to "program" each Keystone Receptacle with some assortment of runes, for example, my home base gateway is 3 blank runes, and my Ice Castle gateway is 3 blue runes. To program a gate, simply sneak-right-click the keystone receptacle with an open hand to open up the interface. You will see three slots for runes, just pick up the rune you want to program it with and attempt to drop it into the slots in the desired order. The receptacle won't actually take the rune, it will just record that rune in the respective slot. Once you do that, you just need to do the same thing to your keystone itself - this works MUCH better if you have a rune bag in your inventory, just put all the runes you plan on using in the rune bag, and its interface will open up automatically when you open the keystone (sneak-right-click with the keystone to open it). With the runes in the rune bag, drop then in the same order of the portal that you previously programmed, give it a name, and click the page-looking button just to the left of the text box in order to save your programming. Do this with as many combinations as you like, this way you can just click the right or left arrows in the keystone interface to select your destination instead of manually recalibrating the keystone.
NOW... after all that craziness, it gets easier. With the keystone in hand, stand close and just right click the keystone receptacle (with the desired rune combination destination set beforehand), and you should see a classic portal open up (sometimes you won't see it, just try walking through anyway - it takes a few tries sometimes), step through, and POOF! You made it through!
Now, about the alternate energy source, I usually make a fully tiered Celestial Prism, and I link it to a mana battery, then I link the mana battery to the keystone receptacle (this is easier to configure if you make some magitech goggles and wear them on your head slot). The Celestial Prism will charge all day (unless you use moonstone blocks; I go with emerald blocks for the best daytime charging), it will fill the battery, and the battery will fill the keystone receptacle, thus ensuring that wherever you go you'll always have a fully charged gateway! A tutorial for making the Celestial Prism can be found here:
http://am2.wikia.com/wiki/Celestial_Prism
Hope this helps!!!